hi, i'm new here

, and to subarus.
i'm currently thinking of upgrading my car situation to something awd. i've narrowed my ideal choices down to one of 2 things. a GC coupe, which i would swap the motor (eventually) or an 04-05 STI.
i have recently seen STIs go for 18-20k, which is barely within my budget. my question is if its a good idea to go for a cheap sti, or is that a huge money pit? would they be beat on, high milage and have lots of problems or are they pretty solid cars?
i'm not in a hurry right now, so i can wait for prices to come down a bit (if they will, i have no idea about the market for these things), oh and sorry if this is a common question, i searched around a bit, but found nothing conclusive.
Thanks!