I like justinh's suggestion of first plugging those gaps.
Perhaps some CAD (cardboard aided design) and trial runs for cooling effects would eliminate the need for cutting?
I'll do something with that area, but I'm not sure what. I wish I could move my cooler back six inches, but I can't, damn-it.
Hey Ron, I used a Roto-zip tool which came with a hole-cutter attachment. Basically an overgrown dremel, and yes, cover yourself especially your eyes and lungs!
Danny, I'm changing how my cooler sits, so I won't have to cut into the body. I'm now going to mount it horizontal and tucked up just in front of the battery box. I plan on welding up some brackets this weekend. I'll also have to fabricate a scoop to force air up into the cooler's fins.