High end brands appear to have more minor problems partially because of who they sell to. Mercedes customers are more likely to take there car in than a subaru customer, especially if you mod your vehicle at all.

This is all just my opinon, the only fact I have to back it is a friend of mine who owns a mercedes has taken it in before because of minor problems, when it was brand new the coolant kept going low, no leaks just went low. Air pockets is what I think it was, my WRX did the same thing. He took his in, I added fluid.