2FastLX-Call MAc they will glady replace your rusted tips, they are replacing mine.
I have had the full exhaust long tubes and H-pipe catback and all on for over a year and they fit and still look great. I did have my MAC headers ceramic coated inside and out though
I didn't have any problem with the install their system fits much better then my old Flowmaster American Thunder.
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My Ride Check Out My Site 91GT, Holley SysteMAX II Kit-Heads 2.02" x 1.60",Full MAC exhaust 1-5/8" Long tubes, 2-1/2" O.R H-Pipe, 2 1/2" cat back, 12" K&N Filter, RNH PERFORMANCE Ram Air, Ron Davis Radiator, Full Suspension,3:73's, Welds, Best on new motor-12.60 @ 108, no traction 1.98