Any technical caveats or performance suggestions in having a M5/6 head rebuilt? Aside from careful machining for replacement of worn guides by a qualified M-head specialist, are there other weak or troubled areas to consider? Any suggested shops?
I'm planning on removing and installing the head myself. How difficult will this be? I've rebuilt a few low-tech engines (as in MG), and serviced my 535, but am not familiar with the M5. Pulling the head seems straight forward enough. Are there any caveats in dealing with install/removal of components?(intakes, etc). Resources?
Also, has anyone used a Metric Mechanic M5/6 head? If so I'd appreciate hearing from them. Finally, are the performance increases from using high flow ported heads accurate? I've heard that with the high flow head, a JC chip, and a decent exhaust you are in the 300-320hp range?