Powder coating

^ yeah degreaser/wax and grease remover pretty much the same thing. I used the degreaser from Repco which I found provided a very strong bond with the primer.

Also in addition to above, to get the best durability possible - the first sand of the wheels should be done with a medium grit, say 180, which will provide an abrasive surface for the primer to 'cling' to. Once you've primed it, wait for it to dry and lightly wet sand it with 600-1000, making sure you don't sand off the primer. Hit it with wax and grease remover, apply another coat, then repeat with 1000-2000 grit sandpaper. Then apply color/ clear.

The only thing that I feel I'd have trouble with is in between the double spokes, i have e90 m3 wheels, if you look at them it's gonna be pretty hard to get into thoes tight areas. Any tips?? Also do you just do the front face of the wheel or do you do the whole thing with the tyre off?

Nah man should still be the same, just try and sand in the gaps as much as possible, the more sanding the better the bond and the finish. You can leave the tyre on - I used a deck of cards to wedge in between the tyre and rim.. I did the front surface and all the inside of the rim. You should paint the inside and outside of the wheel as any differences in the thickness of the paint application between coats can lessen durability and sometimes cause flaking. So a nice even coat all over. You may need 5-6 cans of color spray to do the face of the wheel + inside properly.