well lets see here....
boxer layout engine with AWD drivetrain trying to stuff it into a chassis from a FWD inline 4 vehicle...
have fun, the custom fabrication would be a b**** (thats being nice about it, and assuming it would actually even have a chance in hell of fitting...as I dont know the measurements of everything off the top of my head) and youd need ALL new ECU, wire harnesses, guage cluster, etc...
if you want an easy way to blow up to 50k and countless hours of professional time work, go ahead.... otherwise just sell the car and BUY a WRX...
this is not meant to sound mean, but if youre asking that question, you dont have the skill to do it anyway... dont bother thats my opinion...