get the 325i and try and get one with the Euro bumpers the US diving bumpers are horrid. Power wise it will be closer to the 328 than the 318 and avoid the 320 as their a waste of time. Get a manual and you'l be alright. 325e model is slow but is handy if you want to do the 2.7 conversion depends if you want to spend the money on a project or just get something that you can just drive without spending much £££.
Your Ride: `00 540i6 Alpine White, `96 740iL Aspen Silber
the diving boards don't look that bad when you tuck them in all the way. i also painted mine all black so the ugly chrome doesn't show. Just find something in your price range in that body style. I'll help you with the work. (I won't do it for you, but i'll help...) if you get an 88 or later with the diving boards you can easily convert to plastic when money starts coming in again. I am satisfied with my 86 with the US DB bumpers but you most definitely have to tuck them