i painted the wheels on my 106 black from silver and its really easy.
I done it the "quick" way as i had to leave the next day for a show so far from the best but....
first of all i taped off the tyre (take your time as if you miss a bit its very noticable at the end), then got a good grey primer (acid edge rings a bell), i gave mine 2 coats drying and sanding in between in my specially made booth (2 clothes horses with sheets and 2 hair dryers
) then i used a black wheel paint from halfords, gave it 2 coats and jobs a goodun! your meant to leave it 12hrs between each coats but i done 4 coats in 1 night and drove 500+ miles the days after.
It obviously isnt as good as powder coating but no-one could tell the diffrence without getting really really close (and they were serious car buffs), 6 months on and theres a few chips but overall for £20 they still look really really good! id definetly do it again!