You can go a twin 2 1/2" cats back system with two straight through hotdogs on the front and a straight through muffler on the rear. Doesn't drone, nice note and not overly loud. I can do one for $650.00 inc shipping to QLD. Mandrel bent, with twin stainless tips that are bias cut rolled in, to suit the angle of the bumper. The brand is Manta, practically identical to Redback.