Mr. Waffles 
2006 BMW M5 Sedan 4dr Sedan (5.0L 10cyl 7AM)
The best financial mistake you should make.
 Look. If you're in the market to lose 2k in value on a car (picked up for 16k, traded in for 13k and 1k tax), tempt fate with a looming expensive repair (thankfully I never had one while I had it), and have everyone you know collectively hate everything you love about your money pit, this is without a doubt the car for you. Don't take any of what I just said as me saying you should steer away from this car. Losing 2k on this car was worth every penny. The way that engine revved was out of this world. The exhaust note simply wasn't something that could have been recreated on any other engine and is probably what I loved the most. The car just builds speed faster than anything I've ever been in. For a 2 ton sedan, it handles it's weight as if it were a little roadster. And when you're in a corner, the active side bolstering is both a nice party trick for passengers as well as an absolute (to me) necessity when cornering hard as it allows for both a relaxed feel when cruising or that nice race car feel when driving hard. And that transmission, definitely jerky to drive in traffic and at slow speed. But when cruising and driving at 10/10s, I feel it's just mated perfectly to the engine and car no matter what anyone says about it not being a "true manual" car. Definitely want to keep both hands on the wheel when ripping it at 170 mph. Trips to the bmw dealership every 800-1000 miles or so was annoying to get a quart of oil as the engine loved to drink it as well as gasoline. Sometimes at the rate of 8 miles to the gallon. Passengers were never a fan of having to wait to warm it up or shut it down or pretty much anything that involved the car moving as it was apparently uncomfortable. But the way I saw it, the car was originally built to only really have a driver to go ponder the limits of mortality. The only reason it had 4 more seats was because someone at BMW was insane enough to go "You know what the driver needs? The ability to instill fear into others, 4 people at a time." All in all, if you can afford to pick up even a questionable example in your budget, do not hesitate. Buy it, enjoy it as long you can. The 6 months I had mine were worth every penny I lost.