The 325e isn't the Super ETA. That's a completely different car.
The early 318i is M10 powered; the latter 318i/is is M42 powered. The 325is was avaible from 87 on, and you can't get them for the model year 91. There was only the 325i with the sport package.
I'd personally look at the 318is or the 325is. They take the less work to put them where you want them. The 325e is cheap, but it's going to take more work. Truth be told, I wouldn't look at the early 318i unless you're going to do some serious work.
Metal bumper cars can get the M-tech 1 kit with the smaller european bumpers, but the plastic bumper cars look good from the start.
That's a very very basic lineup. I'm not going into the 325es or the Super ETA. I'm assuming you don't want a cabriolet, but if so, just ask and I can tell you somethings about them.