Just finished my swap.
2002 WRX EJ205 into 1998 Legacy GT wagon.
Notes: (I'll add to this)
-I used the stock LGT 5 speed transmission. I used a clutch disc, plate and flywheel from a 2006 WRX
-Wiring was done by iWire. Brand new OEM bulkhead harness from the Legacy, complete donor chassis harness
-Taking the dashboard out sucks. Label everything. Every screw, every connector. You don't want to put it all back together and realize you missed a plug. Twice.
-I used a first generation Legacy turbo crossmember. The engine will sit higher than it does in the WRX engine bay. This is ok. The hood closes.
-I used the factory Legacy throttle cable (DOHC) and bent the WRX throttle cable bracket slightly so the cable would reach.
-I did not hook up the cruise control. Hopefully I wont miss it. The engine bay is cluttered enough.
-Relocate the PS pump reservoir. Easy enough.
-To retain the factory MAFS and airbox, I used the lower half of the Legacy air box, and the upper half of the WRX box.
-I had originally tried the "hack" method for the coolant lines. I cut the spring out of the radiator cap, added a second seal, but could never get it to completely seal. I ended up deleting the waterbox by the intake manifold. Just run a section of hose from the turbo water pipe to the crossover pipe, and set the radiator up like normal. So far so good.
-Invest in plenty of zip ties and assorted sizes and lengths of rubber hoses and clamps.
-The engine bay gets tight. A set of slim fans might help with clearance up front.
-My TMIC fit without any modification to the engine bay. However, to use the duct for the hood scoop, you'll need to cut and drill to get it to fit.
-Burp your cooling system afterwards. Theres a step by step procedure somewhere on a forum.
-I haven't installed the AC condensor and lines yet. I have all winter to procrastinate.
Oh yeah, and of course it was totally worth it. PM me if you have any questions. This job will be burned in my memory for a while.