[ChiltiCoatl89]

For Reference, here is a DIY Kit from FCP, Most of us 5er Owners use ECS, and mainly FCP Euro, and we highly recommend FCP if you haven't already due to their lifetime warranties. (ECS has it as well to some extent) There is also a basic Kit without a Valve cover and its Definately less expensive. Plenty of Videos and even a video from FCP Euro on how to Walnut blast our N55s.