EVGA does a great job with their coolers, especially the FTW3 and Hybrid series. I see no reason for you to even try what you are attempting.

Getting even better airflow into and out of your case and setting that up optimally is going to net you more than trying better what EVGA has already done.

Re-pasting the GPU with a known paste great for GPUs and better thermal pads are only going to gain you a couple of C too. Like I said, EVGA's cooling for the FTW3 and above series is spectacular IMO.