plenty - first make sure your cans not a non reference card (blue PCB) then make sure your card can run stable at the clocks on the MSI bios - other then that, i dont think there are any serious issues to run into unless the flash goes awfully wrong and you brick your card.
there are probably millions of people out there that do the same thing - a few members here have also flashed MSI cards with the ASUS 5850 TOP Bios's - the 5850 tweaking is pretty old hat now. so theres bound to be threads about tweaking such as the 5xx0 series clubhouse. - the search function is your friend