Kayry, I just completed IMSG (only my second tri) in very warm weather (90 degrees at the start of my run). Like you, I'm a stronger runner (albeit a slower with a PR of 2:55). The heat at IMSG sucked any will of doing a sub-4hr marathon. I just wanted to finish. I did well on the swim and bike and passed nearly 200 on the run. I saw many strong swimmers and bikers push too hard and bonk in the run/carted away to the med tent/SAG wagon, etc.

I don't profess to be a race nutrition expert. Whatever you do this weekend, STICK to a conservative nutrition plan and pace. In the end, you may not hit 10 hours, but you'll be much happier with a 10:30 than a DNF.

Also, get sun lotion REAPPLIED out of the T1 tent. The sun burn on my upper thighs is the only thing that hurt 2 days after the race. I've got scabs now.