So im going to be swapping the drive system in my brat with one from an early 2000's wrx, and im currious how difficult a certain modification would be. i would like to keep the abiloity to select on the fly 2wd and awd, so it would be a slurr of a 4wd system and an awd system. is this a feasable thing to attempt?

The stock 2wd/4wd transmission will not hold up under the power/torque for the WRX motor (for very long)... heck the gen 1 WRX transmissions even had trouble holding the power.

 

That's why the swaps you see are are AWD.

 

Good luck.