2003 wrx engine swap

**jordannn1233** · 01-04-2013 10:05 AM

I have a 2003 wrx with a blown motor does anyone know what the best a easiest way is to go with that I would like to put an STI engine and tranny in it so any advice would be great. Thank you!

**SD_GR** · 01-04-2013 10:25 AM

Buy an intact wreck. Instead of swapping mechanicals from the STi to the bugeye, swap noses from the bugeye to the STi.

This saves you the hassle of swapping an entire motor, entire gearbox, and most if the driveline.

Or search "hybrid build" for the motor and forget the gearbox.

**jordannn1233** · 01-04-2013 04:18 PM

Well the car is fine just needs a new motor but if I found a deal on a still motor and tranny wanted to know what would need to be done.

**MainFrame** · 01-04-2013 04:23 PM

You can do it if you swap everything over, wiring and ECU included.

**jordannn1233** · 01-04-2013 04:59 PM

What years am I limited to. Just wondering because I've been told that after a certain year you have to completely change the differentials and everything.

**zax** · 01-04-2013 07:31 PM

Originally Posted by jordannn1233

What years am I limited to. Just wondering because I've been told that after a certain year you have to completely change the differentials and everything.

Consider purchasing a full EJ205 shortblock or rebuilding the motor if the heads are in good condition. A full long block swap from the STi (ECU and harness swap required) is more trouble than it's worth IMO. As far as STi transmissions go, you will be able to utilize your stock R160 rear diff IF you use a 2006 STi transmission and a 4EAT driveshaft. You will have to deal with your half shafts. IMO if going through all this, you should consider selling the bugeye and purchasing a full STi. The price will be similar and you'll end up with a car you can actually resell.

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**MainFrame** · 01-05-2013 10:16 AM

You're not really limited to any years, you just need to swap everything over (unless you want to do like Zach said and keep the r160, but if you're going to the trouble and cost to get the six speed then it doesn't make much sense to keep the inferior rear diff).

For the engine you will need the entire longblock, throttlebody, turbo, TMIC, both complete wiring harnesses, ECU, etc. For the transmission, I would personally go with the 07+ six speed because it has better ratios. You will need the transmission, shift linkage, clutch, flywheel, axles, driveshaft, rear diff, hubs, bearings, wheels, DCCD controller, etc.

It would be cheaper and easier to just buy a STi.. but to each their own. I'm working on my own version of a bugeye on steroids. In my case I decided AVCS wasn't worth it (the ej205 heads flow more in the first place), so I just built a hybrid motor. I'm still saving for the driveline swap, I figured it all up and I'm going to be looking at around $8,000 to get the STi transmission in there how I want it.