Usually, the latest driver is the best.
However, if you say you had it better with a older driver in your rig and if you donīt mind or donīt take advantage of whatever this new driver has to offer, keep the one you had the best experience with, no problems there.
Your two 8800īs could/should provide you with better perfomance if the game takes advantage of SLI.
I use a GTX295 which is basically two hybrid GTX260 and perfomance is pretty good, IMHO!
Could you get a second 260 and use SLI? That should be unexpensive and would increase perfomance quite a bit, taking advantage of SLI improvements in newer drivers?
If not, maybe a newer, faster graphics card or going back to the driver you prefer.
Newer drivers are more useful to new hardware or if youīre having some problem with a specific game/software that you know was solved in that driver, so as i said, if youīre satisfied with the older driver, go back!
Thanks for the game link, didnīt know but will take a look!