So apparently the M6 has one of the worst residuals on the market. Similar to 6 figure Mercedes, these cars are typically worth only about $45k within 2 or 3 years, even with low miles. Take this example from the 6 series classifieds:
http://www.6post.com/forums/showthread.php?t=1394096
Priced at $46.9K for a car that was $131K when new and no takers thus far! Car seems to be in good condition with only about 36K miles, MY2013, though there was a weird electrical issue that was repaired along with spark plugs replaced at 20K miles. All done under warranty, and the car appears to be still under warranty, but not for much longer. Maybe I should have gotten one of these vs. a new 340i lol. What do you guys think? I may be helping the poster to sell his car!