I took my 335i in to the dealer last week due to shaking when Turbo's where kicked in. They informed me that my wastegates are bad and need replacement. The cost is over $6000 because I am out of the 82,000 mile warranty. I picked up my car 1 hour ago and paid the cash. On my way home, decided to try out my new turbos and my vehicle is doing the exact same thing. Shaking badly and engine light came on (didn't even make it home from the shop) I am thinking about putting a stop payment on my $6000 until the problem is fixed. Any suggestions?