I just found the ultimate BC2 tweak guide and thought I would share with you.

Link to the guide: press here

I have installed one of the drivers and made some of the network tweaks and must say it runs great. No major fames drops even 1920x1200 with 114 - 130 fps no frame drop with smoke etc. I have also deleted the dx files they mention in the guide.

so go ahead a try it out. Some of the tweaks might be a bit hairy to understand.