Sorry guys, I know it's a diy but I been looking and thinking about it for days and I need to share this info with everyone here.
I was very hesitant to buy the first bmw twin turbo engine, because I know how sensitive turbo's are, and I know that you need to warm up the turbo well enough before moving or else you will damage your turbo's. So ever since I got my car, I wouldn't move after startin' the engine until I hear the valve actually open.
BMW used week wastegates for the turbos and if you don't take care of them, I can guarantee that they will break, many peopl eare facing this problem and selling their cars, and getting turbo's replaced under warantee and still having that horrible sound coming from the engine.
http://www.e90post.com/forums/showthread.php?t=310531
I would never move the car until the engine have fully warmed up and the exhaust valve opened, try it, leave your window open and wait for 5 minutes and you will literally hear the valve open and the sound change.
Peace out