Get a e30 as DD and keep the M, one of the best fun(make sure its 5spd) little cars to drive and gets good gas mileage, and its not boring to drive like a Camry. Also e30s are cheap, you can find really clean ones for about 3K, if you are a DIYer then find one that needs a tune up for 1Kish and do the work yourself (timing belt, waterpump, brakes, etc). A 325e gets close to 30mpg, I had one and am looking for a cleaner 325is for a DD
check
http://www.r3vlimited.com/board/forumdisplay.php?f=142 and your local craigslist for finds
Save the M