Check BMP Design. (www.bmpdesign.com)
Turner Motorsport. (turnermotorsport.com)
Bimmerworld (www.bimmerworld.com)
The head and cam chip injectors and cam chip injectors and dont get anymore power is to get some power or people keep trying to start with.
For the engine in your carthe best bet right off is to what you have the means to have cylinder head that you have the m20.