In my opinion, an E30 is the most fun you can have driving a Bimmer. For 3500 buck, a 325e/es (1984-1987) would be a good starter car. There's tonnes of torque, and with a chip and K&N air filter you can get about 200 ft/lbs. BHP isn't too high (121) but the thing will lay rubber, no problem. Put a nice exhaust on it and the 2.7L makes a nice growl. As far as reliable goes, the only time it crapped out on me is when the water pump/alternator belt snapped (but only because the alternator mount broke.) If you enjoy adjusting valves, that'll be about the only thing you'll have to do to get 'er running properly. Gas guzzler too, but to buy a used one, you'll get one at the price you wanna spend. I don't think you'll find a 3.3L straight six 2 door unless you buy a 6 series... but you won't get one of those for $3500. You might be able to score a 318is for $3500 (1989-1991) This car has a timing chain, so you won't have to worry about your timing "belt" breaking, which you should change first thing if you buy a timing belt SOHC car. The 318is has 136bhp DOHC 16valve, 2 doors, and is a load of fun to toss around. It'll be pretty good on gas, and comes with sporty suspension, sport seats and a nice euro body kit. No chrome bumpers. All E30's are super easy to work on, and parts are easy to come by. The 318is has a lot of upgrades available, including a multi throttle intake (from BMP Design) chips, you name it. Parts are a plenty for that engine, as it was used in the E36 318i/is and Z3. Speaking of which E36 are coming down in price!
(If you go with a 325e, I've got a Turner Motorsports chip for it that I don't use any more... and a spare engine... and tonnes of barely used parts lying around in my garage. (replaces a bunch of parts, and then wrote the car off)
good luck... lemme know what you think.
