yup, wouldnt be easy at all, you'll need, a rear diff, 6 speed axles, depending on year, you may need hubs, rotors, wheels, clutch, shifter linkage and shifter assy....basicly what we're saying, is its not worth it, at least not into a 2.5i
6mt tranny 6mt shift linkage 6mt clutch/flywheel Auto driveshaft 6mt tranny mount- just the mount, NOT the crossmember 3.90 rear end - this can be done fairly cheap. You can buy a 3.90 ring and pinion, or go to the junkyard and get a 3.90 rear diff from something and swap in teh ring and pinion to keep your VLSD Depending on your car, you might need axle stubs for the front axle shafts. If your 5mt has stubs for your axels, you'll need them. If the stubs are part of the axle, I think you're fine. As far as a DCCD controller goes, you can drive without it if you want. I've been going without it, but that straight 65% rear-bias can get interesting at times, especially with an open rear diff. Using the factory controller really isn't an option because it gets several inputs from the ECU, so you'd have to give an STi ECU enough inputs to be happy and supply the DCCD controller with what it needs. PITA, imho. A guy from nasioc makes controllers, which seem pretty decent. I've got one on the way. http://www.dccdpro.com/