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So you've just picked up your Celica/350Z/Veyron and you're thinking, "But it needs more power!!!" Where do you start? I'm going to make this guide about as universal as I can so that anyone with an N/A car can garner something from it. There may be certain quirks or parts to your individual car that need to be dealt with, so always do a little extra background research on a part before you decide to lay down your cash for it.

So what are we looking for? What we need are new high-flow parts that can replace your old restrictive ones that came on your car from the factory. Restrictive how? Restrictive in the sense that it either hinders your engines ability to pull in fresh air or push out exhaust gases. Remember, colder air is better air since it is more dense, thereby allowing more air to be packed into your combustion chamber. The more air that gets packed in, the more power you can produce, provided you have the correct amount of fuel to go with it. Adding the right amount of fuel to your combustion charge, which is called your air-to-fuel (a/f) ratio, is vital to creating power safely and efficiently. If you don't have enough fuel, you can encounter what is called a "lean" condition which can burn up your valves and leave you stranded on the side of the road. Too much fuel and you'll run "rich", this can lead to a loss in power and other worse things in richer conditions. When you add less restrictive parts, your a/f ratio changes and in some cases you'll need to compensate by retuning your fuel map or adding a piggyback fuel computer. You'll also need to pick up a wideband O2 sensor and gauge so that you can tell what's going on with your a/f ratio, otherwise you'll just be guessing. Along with increasing the amount of air coming into the engine, you also want to get the gases going out. The quicker you can get your exhaust gases out of the engine, the more room you have for fresh air and so it continues.

Stage 1
These modifications will bolt onto most cars without the needed use of an aftermarket standalone or piggyback ecu.

Cold Air Intake - This should replace the box filter unit on your car and will ideally locate the filter in a place where it can take in fresh cold air from the outside. Look for intakes that don't utilize a lot of bends or kinks. Also, be sure to stick a good filter on the end of it. Personally, I don't like wet filters that require you to clean and oil them every so often. If you over oil a filter, it can make the filter more restrictive than the stock intake you first started off with. For this instance, AEM's Dryflow filters are my pick.

Exhaust - A lot of exhaust systems are fairly restrictive so as to keep the noise down while driving, so this is a good mod that you will probably be able to tell the difference from right away. A catback exhaust system replaces exactly that, the exhaust that starts from the catalytic converter all the way back to the muffler tip. Again, you're looking for a system that doesn't have a lot of kinks or bends in it and has a fairly open canister on the end. You can also go ahead and have an exhaust shop make you a straight through exhaust, that is a certain diameter piping from your exhaust headers back. Notice that this will be MUCH louder than your original stock exhaust and is only recommended for someone who has already installed a catback system. A good diameter for your exhaust can range anywhere from 2.5"-3".

Headers - With this, you're looking for a proven set of headers that will improve exhaust gas scavenging and keep exhaust gas velocities high. Look for a set of headers that have been ceramic coated. There are other coatings, such as high-temp paints and chrome plating, but both of these will wear out after time and don't offer much help. Ceramic coating helps lock in the head which in turn allows the exhaust gasses to move more quickly.

Lightweight Flywheel - Think of this part as not really generating power, but giving you back extra power that your engine was already making. While your car has to use energy to push the mass of your car, it also has to use energy to get the internal parts of the motor going. By swapping in a lightweight flywheel, you're reducing the amount of mass that the motor has to start moving, thereby giving you extra power. This is akin to the concept of "unsprung weight", but that will be covered in a different thread. Basically look for a name brand lightweight flywheel that people have had good results with.

Underdrive Pulley - This also goes back to helping your engine not have to work as hard as it does. You'll only see a handful of HP from this mod, but every little bit helps.

Spark Plug Wires - Depending on how well your stock wires work, you may or may not see much of a gain from switching to performance wires. These types of wires are intended to make sure that all of the energy you're sending to the spark plug makes it there, providing for an optimized spark and thereby burn.

For most cars, a retune of your ecu or a piggyback fuel controller won't really be necessary to get by with what you have, as a lot of stock fuel maps are set a little rich to begin with.

Stage 2
These mods will help better utilize what you've done above and may or may not net good power gains on their own.

Standalone ECU/Piggyback/ECU Reflash - These products are used to change the valuables in your fuel map so that you maintain the proper a/f ratio, thereby giving you the most gains in power possible with the parts you already have. Which item you want to use relates mostly with how far you want to mod your car. If you're done after Stage 1, then you can consider reflashing your ecu. This basically takes a fuel map that has been tuned for a known set of mods and puts it on your stock computer. If you think that you probably won't progress much further, but may pick up a part or two more, then a piggyback may be the thing for you. A piggyback is a computer that works in conjunction with your stock ecu, and can change the amount of fuel being used by either modifying the injector duty cycle signal or the input data signal that the ecu is receiving. If you know that you will continue to heavily modify your vehicle, then a standalone ecu is the way to go. This replaces your stock ecu with an entirely new one that utilizes tuning software to change a multitude of parameters. When shopping for an ecu, it's important to know if there are any tuners in your area who are familiar with one system or the other, so ask the tuner who you're going to use before you buy something.

Port Work - This includes porting your intake manifold, throttle body, mass airflow sensor (provided you can tune for it), and heads. This can be a cheap and easy way of gaining a few horses if you have the right tools. Basically what you're doing is opening up your intake tract so that your engine can suck in more air. I don't suggest porting your heads by yourself, as you can really screw up how your heads flow with bad porting work, so see if there are any local shops that you can have port your heads for you. Many stock heads are extremely restrictive and have rough runners anyway.

Stage 3
These mods will get you closer to what I would consider as a serious street car/mild track car.

Intake Manifold/ITB's - Again, your stock intake manifold may be another large restrictive part on your engine. I know on 2zz Celicas that a new manifold can net you anywhere from 20-25whp. Individual Throttle Bodies are another route to go as far as the intake is concerned, but I can't really comment on those since I've never used them.

Cams - Cams can not only give you a great gain in power, but they can help rearrange your powerband so that the power comes in at the right moment. Different cam profiles will vary depending on what your goals are, so research different cam profiles for your car to figure out which one is right for your application. Also depending on what grind you go with will determine what supporting mods you'll need to add as well.

Heads - This is another big part that can net you great gains. I mentioned porting your heads earlier and this is pretty much the same thing, only you're buying off the shelf heads that have been designed from the get go for high flow. Performance valves and springs can also be utilized while swapping out for new heads.

High Compression Pistons - These pistons will raise the compression in your engine, which will in turn raise the amount of horsepower it puts out. While this can give you decent gains, some drawbacks include having to use premium octane fuel, along with the fact that if you go turbo or s/c, you'll have to remove them for regular or low compression pistons.

Nitrous Oxide - There is a huge stigma surrounding the use of nitrous, mainly due to improper installs and general lack of knowledge by the user, which often results in catastrophic damage to your engine. First I'll say that while it can be easy to screw something up while using nitrous, when used correctly, nitrous can be just as safe as a turbo/supercharger setup. With this modification, nitrous is injected into your engine which does one of two things. First, it super-cools the intake charge which makes the air more dense. Second, nitrous oxide is comprised of two atoms of nitrogen and one atom of oxygen. When the right temperature is reached, the molecule breaks down, releasing that oxygen, which can then be consumed in the combustion process. Again, you'll want to utilize tuning, but a small 50hp-75hp shot can sometimes be safe as well, especially if using a wet kit.

Stage 4
These mods are meant for the all out race car and may not be suitable for the street.

Titanium Rods/Valves/Retainers - These parts will help cut down on parasitic loss, freeing up more extra power that you already had. They also have the added benefit of being super strong, which is good since by now you should be making gobs of extra power compared to what you had to start with.

Lightened Crank - Again, you're freeing up more horsepower by cutting down on parasitic loss.

Polydyn Coatings - Polydyn makes performance ceramic coatings that can be used on your pistons, heads, valves, intake, and exhaust. They also make oil shedding coatings that can reduce even more parasitic loss.

Bored Cylinders - This is a major modification to the block of your engine that bores out the diameter of your cylinders. You'll need to replace your pistons with larger ones, obviously, but this can give you excellent gains as well depending on what you overbore the block to. This is often done with the following mod.

Stroker Kit - This is a huge modification that replaces many parts of your engine in order to increase the stroke, which is the length of up and down movement made by your piston. Normally this is only done on larger displacement engines that don't reach very high rev limits, as it involves changing the rod angle and piston speed.

Well that just about does it. If you have any questions about something here, or want to know about something that I didn't post up, feel free to start a new thread or send me a PM.

I am assuming that you snatched this from somewhere and did not type it out yourself, so I wont hold you accountable. If you did type it out, then I have a bone to pick. I dont know about all cars, but Miatas specifically take very well to a small timing bump. Starting out at 10* TDC most tunners(is that the word we are still using?) go to 12* or even 14. I personally am at 12*, but the car was like that when I bought it, and I run slightly better gas.

Yes, I typed all of the above post. But what was your bone to pick about? This is a list of aftermarket parts that you can buy to add on to your car, along with a short description explaining what they do. Adjusting your timing isn't an aftermarket part that you can buy in a store, so I didn't add it to the list.

I didnt see you mention anywhere that it was for stuff you have to buy.

Sorry, I guess I didn't make that clear enough at the start. Advancing your timing kinda falls under tuning, which really needs a whole new thread all of it's own. If you advance it too much or too little, you can have serious to major problems, and it really varies, even from different cars that are the same model. Likewise, I didn't include fueling components or any other support mods, as this can differ greatly from car to car as well.