You'd be fine with an E30. I've been thinking about doing the same thing.
They're fairly easy cars to work on... parts are readily available and won't cost you an arm and a leg. You just have to search around on other enthusiast forums and craigslist. You'll find what you need--- theres a huge following for e30s.
I can't speak for specific problems since I haven't owned one or seriously looked into it too much but I'm sure some of the other guys on these boards will chime in.
1997 M3 Coupe - BMWCCA I-Prepared #22
2006 M Roadster - 23,000 miles and slowly counting