When I purchased my ZR-7S it had already been upgraded with a Two BrothersFlange-On Aluminum canister (MSRP of $372.98). After several years of Atlantic riding the can was able to benefit from some polishing with Mothers Mag & Aluminum Polish, this took care of the bulk of the Aluminum sheathing, but didn’t touch the cast end piece that was suffering from a good bit of corrosion and pitting. To get the cast exhaust tip back up to snuff I used two grades of buffing compound and an electric buffing wheel.