Linustechtips has a video on painting a motherboard. Normally you can remove heat sinks and plastic pieces such as RAM slots without breaking or desoldering anything.
remove them and paint them, not really all that hard. Don't get paint on the contact surface between the component though, you want some heat transfer after all.
Do you still have that dead Sli plus board? If so, then maybe you can just exchange heatsinks? I suppose that the vrm heatsinks and mountings are pretty much similar with those 2 boards?