I cant emphasize how bad the exhaust sounds without the cat.
In the past I would pull the cats off of my 460's. the exhaust would get a deaper more throuty sound. the 6.2 sounds like *** with the stock muffler and no cats.

I woul look towards the Raptor forums. a lot of the Raptor guys are running 6.2l with no cats, lomgtubes and a performance exhaust