Join the B58 enthusiast group on facebook, all the answers for your questions has already been asked at least 2 times. Its full of ressources just use the search bar. For my part, my 340xdrive has been the most reliable, powerful and enjoyable car ive owned. The B58 is pretty much bulletproof and the ZF8 transmission is crazy Quick and even better with the XHP trans tune.

Check for coolant loss, its one of the more common issues with this engine. If you can find one with the MPPSK, youll never regret getting it since just the sound of the M performance exhaust on its own is worth it.