cats?
I am running QTP headers, catted Y and GMMG and I think it's still too loud. I will install a XR-1 on the I pipe to get rid of the drone.
I believe performance loss will be minimal.
What type of muffler you have will make all the difference in the world with drone.
A dynomax bullet muffler can help with rasp, but won't eliminate it. Cats are your best bet.

