the smg is only limited in europe no like on the m3 csl. you can only use 5 times and your warranty is void. but since US has regulations on having functions on cars with unlimited use, BMW lowered the launch RPM in the states to meet US regulations and lets us use it unlimited times.
ive never heard of the m5/m6 being the same. if they void warranty for using it too many times isn't that in terms of limiting a function that we are freely able to use?
back to topic. for the m6 you have to use launch control for the perfect launch. once active it will rev up and all you have to do is floor it and be prepared to shift
