2002 corolla

Well, first off you have the basic stuff:

Intake
Header
Exhaust

That's not going to make a real big difference though...

If you want some power you can really notice, you have basically three options:

N20. This is the cheapest and easiest. It's very noticable power. It's also very reliable when you get a good kit and install it correctly... and you don't try to spray too much. The downside is, you have to fill the bottle up all the time, and it does wear on your engine. Initial cost is around $400-$500. Eventually, you're going to spend more money than one of the following options:

Forced induction. First up is turbo: low boost or high boost. Low boost is around 5 or 6 psi, you don't need to rebuild the engine, but you need a good piggyback computer, turbo, intercooler, BOV, wastegate, custom manifold and piping, etc. This will cost you about $1500 plus $500 for installation at my shop, you're looking at $2000 about. Advatages are lots of power on tap all the time, downside... um.... reduced fuel economy??? LOL

High boost is all of the above plus a low compression engine rebuild. Basically add another $1500 in parts and $500 labor at my shop. Your grand total would be around $4000 and you would have a VERY powerful setup that is also very reliable.

Another option that I have yet to explore is using the supercharger kit for the 2003 Corolla. Since the engines are pretty similar, it could probably be adapted. The TRD Supercharger is $3000-$4500... you can find them cheaper on sale sometimes. The advantage of the s/c is instand throttle response, the downside is that it makes less power than the turbo.

Last option is an engine swap. I put this last since it's probably the most the most expensive, but it's also the most reliable. The reason why is, the engine you put in will have more power in stock form, so it's not being pushed at all. What you have for options is the 2ZZGE from the Celica GTS, Matrix XRS, and Corolla XRS. The problem with this engine swap is that the engine is pretty expensive. If you can find the engine for a decent price, then you just have to worry about installation, which at my shop will be about $1000. You have to add about $800 of custom parts that are made at a machine shop near me. If you can get this engine for $3000, you're looking at about $5000 installed for a very reliable 180hp.

Another swap option is the 4AGE series. While these engines are older, they are more powerful than your stock engine and most likely will be about the same or less work than the 2ZZGE, even though the engine setup is different. These engines can be had for around $1500, installation will be another $1000 plus some custom parts, figure around $3000 for installed. You'll have around 150hp and it will be very reliable, and unique.

If you want to get really crazy, you could swap in a 3SGTE. This is the 2.0 turbo engine from the MR2 turbo and the Celica GT-4, and a few others. They run about $2000 for the engine, installation would be around $1200, and there would most likely be some need for custom parts and a different tranny which you can add another $2000 or so for. For around $5000, you would have 225 reliable horsepower that can be upgraded very easily. The only downside to this swap is that the engine is quite heavy compared to the 1ZZ, so you're going to have some changes in the distibution of the weight... it could through off the handling some.

Now, some other important points. Before you go and start making lots of power, you need to think about handling and braking. Put suspension, brake upgrades, and LSD towardds the top of your list. (LSD is optional depending on what tranny you're going to get...)