That's the main reason I got rid of my AE86's is just the cost compared to the worth of what I was doing to them. I had a blacktop 20v in an 85 GT-S, and with all the cost involved in getting it set up, the value of the car would never break about $4,500. So I sold em off and have plans on picking up an early 70s Celica Coupe in the next few years.
My brother restores muscle cars, and seeing what he's been able to get when he sells one is just ridiculous! Not that someone'll ever be willing to pay $30,000 for a Celica, but I'd be happy with the car feeling like it was worth what I put into it.