I bought my wrx 5 years ago and I have learned the following:

Changing:
oil
transmission fluid
coolant
rear differential fluid
brake pads
rotors
brake fluid

Replacing:
radiator
exhaust
turbo
intercooler
springs
swaybars
millions of bushings

Learned a bunch about:
internal combustion
turbochargers
racing
how cars can be fun as hell
painting
heatsoak
detonation
tuning
how cars can be a pain in the ***


I guess the point I'm trying to make is that regardless of the car, you will learn a bunch if you do enough research and have the right tools. If you want to build up the 2.5i, that's great, I wish you all the luck in your journey. But, after the mod bug takes thousands of dollars from you, you will probably look back and wish you would have started with something else.

Put some swaybars and springs on the 2.5i and make it a daily driver with awesome handling. Then save up some money for a sweet project car! My dream is to buy a porsche 914 and put in an ej257.

 

the bottom line is if you think a wrx and sti are "complete" and setup to be 350-400 whp then you need to research some more. Honestly with your car you have 2 options go all show or set it up for auto x/track/rally x. For power what people have been trying to to tell you is that you will spend twice as much as a used wrx just to get to that stage and you won't even be close to having the power you want.

 

It's not just a motor and trany swap, the cars are so much different, built the WRX and learn that way, by building your 2.5i u won't learn cause your car will make you go crazy, cost u so much and still not be 450whp, I have a full built WRX, full STI everything and then some. Cost with parts and labor I have well over 30k into the car.

 

Ok well if performance for the motor isn't a good idea then what is? I'm not going to sell the car at all so what can I do to make it better?

 

Handling mods

Tires/Wheels
Sways
Struts
Springs
Brakes
Bushings, bushings everywhere
Maybe diffs


All that ****. In that order. And don't be cheap. You'd be surprised how much of a difference a set of good tires can make.

 

I'm running 17 inch enkeis with falken tires. Those good?

 

Which falkens and what size?

 

225/45zr17

 

and what kind?

 

Best be AZENIS RT615K.


But I bet they're ZIEX ZE-912. Which... uhhh... yeah.



When shopping for tires, an important metric is the treadwear. The lower the tw, the more grip the tire will have. But low tw will also have a shorter life. A higher tw will last longer, but won't offer as much grip.

For me 200 treadwear on a performance tire is a pretty good place to be. Race slicks (R-comps) are 100-140. ****ty all-seasons are 300+. I know 200 may be a little too soft for most people, but I feel like it is very DD-able.

 

Just buy an sti if u want power.. Wrx trans and few other things break with power. STi has so many big and little differences or upgrades that it would make no sense modding a wrx to achieve same performance. I had an 04 wex first then i drove an sti and reality struck me hard...my wrx was a commuter car..sti is race car. I bought 05 sti right after test drive and now have a hawkeye...wont drive anything else if u paid me. Especially a rwd turd like a mustang...

 

Tires..bfg gforce kdw ftw!