I do not think you are suppose to powder coat wheels. The slow heat up and slow cool down weakens the wheels, specially on forged ones.

Doing it twice...hmmm

Anyway I dont like black rims...the current color look s really good to me.

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97 E36 M3 SC with 420 WHP (my fav)
02 E53 X5 4.4
08 Cayenne Turbo