I agree that this is a good way to get a professional shine from the TPI Plenum...but you must use a polish compound on it regularly to keep it that way...otherwise, it will become extremely tarnished. Go over it with some NeverDull...buff it out and apply some wax...I use mothers carnuba and it has and will look great forever...same goes for you guys out there with high polished GTA rims. Use some aluminum polish, buff it out and then use some wax. If you don't care to keep buffing it out as necessary, then a shot of clear Powder coat will seal it up nicely. And all you have to deal with is dust and not oxidation on the bare aluminum.

Steve
Streamline Coatings

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89 GTA G92
305 TPI
WC 5spd w/3.45 rear
Accel Cap & 8mm Taylor's
Crane Ignition
Custom 4" Cold Air Induction
Jet Airfoil
K&N Airfilter
160 deg stat/fan switch
Hypertech Thermomaster Chip
Steel Rad
Cat back 3" Exhaust
HiGh FlOw Dynomax Cat