While my 2007 E70 had a number of repairs under warranty or CPO, I'm not sure any of them were common issues. One thing I would check is if the 12V battery has been replaced or not, because the original would be coming to the end of its useful life. I had to replace that at the dealer for $600, or about 10X the cost of replacing the battery in every other car I've ever owned. But I did it at the dealer because it was about $250 to order that type of battery online, and probably at least another $100 at the dealer for re-coding after disconnecting myself.