probably won't find hacked BIOS for the server board as they are meant for stability, though if you do find hacked drivers, make sure you research it so you don't end up with a dead board (eg like if it is actually real)
You'd be a lot better off with a single i7-975 and a high end x58 board for gaming. You say that Intel's high end is too high priced, but you have $2000 worth of AMD CPUs in that built, twice the cost of an i7-975.
Of course, even that would be a waste just for gaming. Why not just get something like an i7-920 or similar and save some money?