Maybe someone installing an aftermarket downpipe would sell you their old one which would be a full bolt on install. My advice is to start putting a few drops of oil or some sort of rust eater on the downpipe bolts each day for a week so when it is time to remove them, they come right out. This has worked wonders for me in the past when I knew I was about to do exhaust work.
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03 GT, STB, GM HD sway bars, 35% tint, GE893(37watt)fogs, Flowtech Terminators, 180 T-stat, ZZP DP & PCM, Ceramic PLOG & Crossover, 18" glasspack, 2007 17" Mustang Bullits 235/55/17 Pirelli PZero Nero, 12" R1 D\S rotors, gutted air box, GTP radiator