Not exactly daily driver, but some of the modifications taken by the French engine specialist SODEMO in offering the new M3 V8 to the LMP2 racing teams may find its way back to some reasonable offerings for the street.
Sodemo develops BMW M3-based LMP2 motor
http://www.motor-sport.uk.com/news.php?news_id=1131
Sodemo site
http://www.sodemo.com/
Wikipedia - Le Mans Prototype
http://en.wikipedia.org/wiki/Le_Mans_prototype