Also looking at a 2009 135i M Sport (Black on Black), possibly signing papers on it tomorrow. The car is from the BMW buyback program (mechanical issues) and only has 22,000 miles on it. Car will come with factory warranty until May of 2013. I'm a 15 year DIY BMW'er and the car drives great except for one flaw that I'm not familiar with - Turbo's. At idle there is a repeat whine of the turbo's - like they are recharging every 20 seconds. The whine starts then after 5-6 seconds it fades out. Is this normal? If not what are possible issues?