Just an FYI:
Small pebbles get caught inside of your wheel all the time. When you have deep dish wheels, this will occur on both side of the wheel face, which means that the "show" side of the wheel will incur some damage over time. If you choose to paint the lips, then you can expect the damage to occur more readily than if you chromed them (chrome is tough).
I think it look pretty cool to paint them; it seems like everyone has chrome lips (including me) these days. However, I just wanted to share some info that may help your choice.
2009 S5 | Daytona Gray Pearl | Black interior | Carbon Atlas inlays |Technology | Nav + | B&O |
Mods: KW V2's, Klassen Leichtmetallrader wheels (thanks Wheel Experts), E-Codes, STaSIS ARB, B&B exhuast
Member of the 315 Club