6 speeds are good but for daily I wouldn't consider it. The auto is so good and the shifts are firm and fast In manual mode. Late 08+ seems to be the best and out of the hpfp range. Check to see if the turbos have been replaced as well as wastegates, injectors and hpfp. Make sure it's running latest software as well. The are monsters with even a basic stage one tune.
The wife ordered my m5 bumper and sides for my birthday. She saw my brother in laws car who just had them out on( same color combo as mine but his is sedan) and liked it a lot.
Here's his car. Mine will be identical except wagon
http://i231.photobucket.com/albums/ee254/ca18det007/Mobile%20Uploads/5330D3DB-A539-4DA7-81DD-AC6C6045AC7D_zpsyuo7dgbg.jpg