I've got the Zalman 6500 and had to tweak the fan mount to get it to fit around my Leadtek graphics card. What I did was buy some 1/2" long nylon bushings and longer screws to push the fan mount away from the card. This moves the fan back away from the heat sink a 1/2" but seems to work fine.
Also, depending on your configuration you may be able to actually mount two fans on the bracket.. I did, but didn't notice much more of a benefit.
My temps are 38-41C at idle and 50-55C at 100% load depending on room temperature...and with the side panel off it will run even cooler.