i own a 02 ws6 m6.
about the cutout. my exhaust setup is headers slp ypipe resonator then catback. i wanted to throw the cutout on the end of the ypipe rite before it connects to the resonator. that way it will have zero restriction also a better sound thus louder. the only problem is the ypipe is 2''5 and the resonator is 3''. so the qtp cutout doesnt bolt up properly on the 2''5 ypipe seeing how the cutout is 3'' what do i do.

 

you could try a pipe expander, or buy a transition pipe for the size you need.

 

See this thread
https://ls1tech.com/forums/generatio...t-problem.html