i'm still not convinced
heres stock manifold, o/r x pipe, stock mufflers
YouTube - 2007 Mustang GT S197 No Cats, Mac X Pipe, Stock Mufflers
and heres LT's, o/r x pipe, stock mufflers
YouTube - 07 Mustang GT longtube headers, no cats
it's from a s197, but principle should be the same...