Love the car if it is a manual trans. Any good e30 is is a hard find these days. I had an e30 318i and an e30 325e and loved both of them. I drove those things into the ground and they kept ticking.

I would personally love an e30 M3, but they are maintenance nightmares. Those engines needs a lot of attention, from what I have read and heard.

The e30 318is is considered by some to be the "poor man's" e30 M3. Biggest difference between the 325is and 318is is weight. The 318is is a high revving 4 banger and the 325is is a little more front heavy due to the larger 6-cylinder engine extending over the front axle. You can actually supercharge the 318is to have more hp than the 325is (if you are into that).

Here is a good webpage for the 318is if you want to compare.

http://www.m42club.com/

Having said that, the e30 325is is a great car and would be alot of fun as a daily driver or a track/weekend toy, IMO.

Also, maintaining an e30 is not very expensive and it is not that hard to fix many common issues yorself. Your buddies e30 M3 is way more expensive to maintain than a 325is.