Ben, If you take the pipes to get powdercoated, then they usually sandblast or chemically removal all the soot and rust before they powdercoat. You could also remove the rust yourself by using Carberator cleaner or Brake Cleaner and then get some High Temp spray paint and do it yourself. make sure you use a clearcoat asfter you paint them.
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Louis Anaya 1992 Sentra SE-R Bluebird SR20DET w/ GTiR Pistons,T3/T04E,Deltagate Wastegate (9 PSI) FMAX Manifold, RevHard FMIC, JWT S3 Cams, JWT Ported & Polished Head, 1996 200SX SE-R Welded & Cyro Treated Tranny, ACT Xtreme P/PL & 6 Puck Disc, Cobra MAF, JWT ECU w/ 4 Bar Fuel Program, MSD 50lb/hr Injectors, JWT Fuel Rail, 300ZXTT Fuel Pump, AeroMotive Adjustable Fuel Pressure Regulator, Greddy Profec B, Greddy Boost & EGT Guages, UR 4 Pulley Kit, Powerslot Rotors, Axxis MM Brake Pads, ES Motor Mounts, Topspeed Short Shifter, Momo Cobra Shift Knob, KYB AGX Struts, GC Coilovers (350F/600R)& 17x7 White Tenzo Shu-4's w/ Kuhmo 205/40/ZR17 Tires