I went from my Dad's low mileage(67K) 2 door 325SE to my (manual) 535 sport , pics below..
http://www.e30zone.co.uk/modules.php?na ... highlight=
If you make the change you wont regret it
Why 325 sports are worth so much more than an e34 sport is beyond me...the e34 is a better car vs an e30 in every respect, comfort, speed(more so at the top end) ,brakes(e30 brakes are generally cr@p)toys and my sport handles far better than my SE did, even on its metrics..
engine wise, id go for a 535 if you can find a good one...they have far more toqrue than the 2.5's and thats more useful on the road in a big,heavy car..I think the later 2.5 had 190BHP and the 3.5 211BHP so there is an admittedly small(ish) gain in BHP
and they aint that much harder on fuel than a 325 - i average around 25MPG, at a constant 100MPH it reurns 20MPG - but i can return 13MPG across town
..and for some reason they dont seem to rot in anywhere near the fashion an e30 does...My 15 year old car has NO rust on it anywhere, not even underneath.