So you are thinking of making a Subaru Impreza WRX faster? You are thinking that you want to have STi speed without the price tag of an STi, am I right? Well let me tell you that this is definitely very possible and thousands of people have already done this. I am here to tell you how it can be done cheaply (under $500), and still retain quality parts.
First thing to do is to make sure that your car is ready to have a bit of modification. For instance, does it have fresh oil, does it have any leaks, etc.
STEP 1
Once the WRX is in shape for some modification, the first step is to figure out what type of engine management you would like to use. If you want to go with easy use, great customer service, and reliability I would recommend the Cobb Tuning Accessport ($700 new, $300-500 used). If you want to go for the best bang for your buck, then definitely use the open source community with a Tactrix cable ($80 new). I would recommend using the Tactrix cable because its cheap, and actually has many more options to change than the Accessport does.
After you have purchased your preferred engine management system, you should now be ready to flash your ECU to stage 1 programming. This changing some settings around, and turns the WRX’s turbo up to run slightly higher boost. Usually a stage 1 WRX will have around 255hp, compared to a stock WRX with 227hp.
STEP 2
The next step in the process would be stage 2, which is the combination of a turbo-back exhaust system, and an engine management system. Since the vehicle is already equipped with an engine management system, it is ready to put an exhaust on.
When shopping for an exhaust, realize that you do not need a name brand exhaust. A pipe is a pipe, the only difference is that some exhausts might be a bit harder to fit. Make sure to piece together a turboback exhaust, which means exhaust that goes all the way from touching the turbo, to the end of the car. So to piece this together a downpipe will need to be purchased, and a catback exhaust will need to be purchased. Buying both of these is crucial to upgrading to stage 2.
My personal recommendations for what exhaust to by depend on what you are seeking. If you are looking for the best bang for your buck, then you can buy an ERZ downpipe (found on eBay) for around $100. This downpipe has been proven time and time again to have great fitment, performance, and reliability, for a great price. For the best bang for the buck catback I would say either buy one used, or buy a brand new SRS or ERZ catback (found on eBay), which have both been found to be great quality for a price of around $200.
If you want to have an exhaust with great quality, great sound, and perfect fitment, then the Cobb Tuning turbo-back exhaust is right for you, but be ready to pay around $1000 dollars.
STEP 3
Use your engine management system to change the current map to a stage 2 map. This will result in around 280hp.
The WRX STi has 300hp, so this 280hp is pretty close to the same power. But the WRX having slightly less power than the STi does not mean that it is not as fast. Let me explain. The WRX weighs 3085 lbs, and the STi weighs 3263 lbs, so the WRX is going to be pretty close to 200 lbs lighter than the STi. With cars, weight significantly effects the power, the lighter it is, the better. This difference in weight gives the WRX a chance to make up a little bit of the horsepower difference between the two.
There is one other factor that makes the stage 2 WRX as fast as an STi. The WRX has a 5 speed transmission, whereas the STi has a 6 speed. This means that to get to 60 mph, it is going to take the STi one more shift than it is going to take the WRX.
So totalling all of those factors, it puts the WRX at around the same speed performance level as the STi. If you chose the best bang for your buck category, you should be at around $450 depending on the specific shipping charges.
