I'm sorry, but I feel really bad for you, Eric. What has it been, 3 years?
Its time for a reality check. If they haven't figured out how to properly build and tune a 335i single turbo by now, it's never going happen. Eric, you seem like a wonderful guy, but there has to be a limit to how much you're willing to put up with. Get your car back, and demand some serious compensation. I think three years of depreciation is worth at least 1 800hp E46 M3