They look really improved, good work!
I have white MOs, and after 5 days not cleaning them at the Ring last Easter (due to the no car washing rules

), they look grey permanently.
I need to do the same to mine. Not sure how long a sprayed on finish would last, but at least you can change the colour as when you feel like it.
I was going to Powder coat mine, but saying that it costs £120 a set locally (blast, clean and coat)... or I could use some rattle cans and spend £20 and just redo them every few months.... hmmm
Si