High Pressure Radiator Cap:

The OEM radiator cap is a 0.9 bar design. Our cap upgrade replaces the OEM cap with a 1.1 bar cap allowing the cooling system to operate at its optimum level.

That's from the M2 web site...is this true?

 

nevermind, found the answer.

 

ttb, where did you find the answer?

 

do a search for radiator pressure cap. there's .9, 1.1 and 1.3. apparently 1.3 is too much, .9 is not enough. double check though.