Im getting a Manta catback Hotdog centre/Muffler to muffler rears, I am installing it myself. Mild steel, on speaking to Manta, there aluminized catback runs the same mufflers with stainless inner core as the stainless version, reckon sound is exact same maybe a tad deeper than s/s. The s/s has a 10 yr warranty and they m/s 2 yr, the 4'' quad tips will already be welded on muffler, so just a bolt on.