there are two things I can alwasy be sure to see at my mechanic's garage:
old tires in the back
a 944 needing work
Personally I think for their time they were interesting looking cars. Growing up I was never a fan of the 911. It looked too much like a VW to me. The 944 and 928 had forward looking designs. Once I started driving cars and not just reading about them in magazines 911's weren't just VW looking cars to me. They sort of reminded of the go karts I went around in as a kid. But 80's and 90's Carreras have become simply to valuable and expensive to consider for racing. Every year they go up in value as do the costs in keeping up with them. Meanwhile the supply of water-cooled Porsches goes up while prices go down, not the maintenance unforunately. But they're as reliable as you're going to get.
As far as racing on a budget, I doubt you can beat the Boxster as far as Porsche/BMW/Audi. An easy car to learn how drive fast in with more than enough power to get you up in the trees. Although I think I'd rather get one of those Toyota FRS for racing. A RWD boxer enigne that can't be anywhere near as expensive to fix/maintain sounds like a winner. Its sorta what a 944 would be today. Subaru BRZ seems to be the spendier version.
http://www.youtube.com/watch?v=xa6-Z8fcPjQ