This morning I picked up a WRX transmission, driveshaft, rear end and subframe assembly from Andy at Grimmspeed. I can now convert my clutch to hydraulic, make use of the entire WRX pedal box, and can use any clutch and short shifter for a 5-speed WRX.
I'm unsure of what driveshaft I'll have to use, but I'll be dropping that tomorrow.
I haven't taken a look at the rear until now. It's not too bad, but the rust makes it look like shit. Once I get it taken apart, I'll go through, sand out as much rust as possible and paint it black.
I also plan to disassemble the WRX subframe, replace all the hardware, and clean up the rusty parts as well. [I want to get rid of those stupid plastic end links too.]
Decided to get the front mount installed as well. The existing bumper beam holes almost lined up. I could have probably made it work, but one of the bolts would have been crooked. Wasn't really feeling that.
Before
Holes drilled, checked for alignment.
Installed with fresh hardware
Done!
Here's a shot from inside the engine bay.
Lines up nicely with the bumper cover support
And one more.

I'm really happy how it turned out. I should have plenty of clearance for piping, and I got it pretty much dead center without having to modify the intercooler bracket at all.