sigma95 
2006 BMW 6 Series Convertible 650i 2dr Convertible (4.8L 8cyl 6M)
Best bang for your buck.
 First of all, you have to know what the 6-series is and is not.It is not a canyon-carver w/ it's porcine weight, but a GT rocket ship most comfortable near three-digit speeds on open road.It's the 2nd most depreciating car on the market, so if you find a good used example, snatch it up quick and thank the previous owner for taking the full brunt of depreciation.No problems and smooth.No car for this $ gets the nods, 2nd looks, thumbs ups, and in one case actual cheers, for it's mere presence.If you're a DIY'er, get on bimmerfest and learn the easy maintenance steps and save even more $.Note: 0-60 is nothing remarkable.60 - 120 is absolutely frightening.