I visited Wheels America yesterday and asked them about about mixing touch-up for G35 18" coupe wheels. Basically, they said it is impossible to mix a touch-up for them. The reason is the factory finish on the wheels. What we think the finish is, is not what it is in actuallity. It is not a dark silver at all. They use a very expensive finish which is only used on a few European exotics like BMW M5's. The wheel is first powder coated black. Then a very light dusting is done over the wheel of a bright HMC silver. The silver coat has to be subtle enough that it just gives a little metallic look to the wheel, while still allowing the black to bleed through to darken the color. While you can put black touchup down on a curbed spot, it will still be extremely difficult to airbrush only part of the wheel. For this reason, they alway strip and completely refinish any of our wheels that go to them. To get the silver to apply right they also spray it immediately when the wheel exits the oven from being powder coated.

04' G35 Coupe(finally in the garage)
6-sp Diamond Graphite/Willow w/Premium

Wheel America actually has several sites around the US. the closest bay to me is the Gulf of Mexico. He didn't say the exact silver coat, just that it is a bright HMC silver they have to buy from Europe. They strip and powder coat only the front side of the wheel(entire facing). They won't refinish just part of it because of blending problems.

04' G35 Coupe(finally in the garage)
6-sp Diamond Graphite/Willow w/Premium