I've NEVER removed the CPU heatsink, I've blown the fan area and CPU heatsink out though, I haven't goto the GPU either, I'm not too sure you should, if you look threw the manual it's kinda a b!@#$ to get at.
I Think the 1.00.10s is current as far as I know.
I had issues OC as soon as Updated the bios. I'm on the Omega 5.6's and I use the OC tool with profiles set up so if I game it OC accordingly and drops to default clocks...