Well the SE is the way to go. The 89 and 90 has single over head cam engines as opposed to the other years KA24E v/s KA24DE. s13 body style (hatch back, coupe, and convertibel) went from 89 to 94. Coupes are a little rarer than the hatch backs. 95 to 98 was the S14.
For what you are wanting to spend, it will be an S13 unless you luck up somewhere or perhapse go to an auto auction. Then an S14 may possibly be had for 3000. I like the S14 a little better, as far as body style.
91-93 is what I would be looking for. The SE is your top line model with all the extras. Some have super hicas, heads up dispaly, alloy wheels, lsd(or is it vlsd??).
The LSD is one of the things to look for deffinetly. Hicas is something you may want, or may not. It is harder to find. Some people like it that auto cross.
Oh yeah, the hatch backs have a problem with rust under the spoiler on the back. It just attracts moisture. Something to look out for.
There are a whole lot more people on here better versed with the in's and out's of the 240 than I. They will pop up later today, I am sure, and fill you in more on the 240, and correct any mistakes I have made.
