Sure NP, just be aware that you will definitely need to hack that one big copper sink into smaller pieces as needed to fit on your VRMs (won't be difficult copper is a soft metal, so you could even just use a good pair of scissors) and you might also need two of them to cover all your VRMs but you'll want to measure to be sure.
And just to be clear cause I thought of a better wya of explaining wha tI meant, if you're currently loading at 61C in games and your GPU core is good up to over 100C then you have plenty of headroom available to you with the cooling on your GPU core, but if currently you applied more voltage as it sits now then your VRMs would be insufficiently cooled for the task and that would hinder stability and not be very safe. With those heatsinks you could safely turn up the voltages without worrying too much about either your VRMs or GPU core, you'd be able to use voltages nearly as high as people on real water.
I'm gonna look at a PCB shot of your card and see if I can guesstimate if one of those copper sinks would be enough.
EDIT: Mmm it's be close so you'll probably want to measure yourself because you might need two, but that copper heatsink would be a great improvement over the stock unisink.
Edited by juano - 8/12/11 at 9:38pm