There's not too much new in the GT500 exhaust system for '13, with the under-car piping all carryover
2.75-inch tubing. But the extra heat and mass flow was enough to threaten the catalytic converters, so part
of their canister is upgraded to 304 stainless steel, and the two "bricks"--the actual catalyst matrices--are
now bonded to the inside of the cat with a heat catalyzing cement.