Any o/r pipe will make your car pretty much scream. Once you get rid of those cats you will never put them back on, trust me
I have the SLP catback myself, and I'm going with either the SLP X pipe with race pipes, or the MT o/r X pipe. I had an o/r H pipe with 2 chamber flowmasters on my old stang and it was loud as crap and had a mean sound to it.