You gotta be careful with saying dealer only, because of the age of the cars lots of dealers will not want to offer a warranty. Additionally some extended warranty companies don't cover over 15 years old.
I picked mine up my 2.0 STI in January. So they do come up, but I spent nearly 6 months watching and waiting for the right one (Blobeye, PPP with cert, not Jdm, low miles, stock, and above all in good nick) . I missed out of a beaut for £11k, and ended up getting mine for a shade over £10k with about 46k miles.
Look for decent history. Money spent, the car taken care of. Get under the car, look for underseal and rust. Check for knocking rear shocks (I got lumped with these but it's £200 for new ones).