Marc H no longer powder coats because "PC tends to be brittle and it will often crack and slough off around the bolts." He paints his.
I painted mine. I simply wet sanded mine down then used a filler primer and more sanding to level and smooth before applying the finish coats: a high-temp silver wheel paint and high temp clear coats. It doesn't crack, apparently.
As for yellowing, Marc had problems with some powder coats that did turn yellow (more golden - almost looks like it was on purpose!). However, there are high-temp clear powder coats available where that shouldn't be a problem.
The wheel paint really contrasts with the old faded green-grey of my stock 90 in this photo - to give you an I-dear.
An unusual shot...
Another look at the color...
Then you could always just polish it like Keith Moudy did...
Lotza options!
P.