Here's the info page for 343.02.02F02
http://www.nvidia.com/download/driverResults.aspx/82983/en-us
Try to install with your present configuration. However, if it won't install "on this system,"
you'll need to change your System Definition to Mac Pro 3,1 to use this installer as per the above page notes. You can change back to the SysDef you had before with MultiBeast my just selection the SysDef option:
To install: Customize > System Definitions > Mac Pro > Mac Pro 3,1 then reboot and install the driver, and
To Change Back: Customize > System Definitions > (select your previous SysDef) then reboot.
Update: The nVidia System Preference pane once again froze Hector while installing the updated Wed Driver. I recommend downloading the driver from the nVidia site using the link above. Then, after the install and reboot, repair permissions.