I have an 08 A6 LS3 Z51. My only mod is the killer bee intake, beehive and cut shroud. I am about to buy LG superpro long tubes and GT4 mufflers. I am leaning toward getting the off road pipes instead of cats. I had longtubes with cats on my A&A blown C5. Is there more performance to be had without them and is the sound louder. My blown c5 had cats and a corsa sport exhaust and im looking for something a bit louder, but not extremely obnoxious. The car will be bolt on only for a year or two then possibly a heads cam kit, or another A&A blower.