The Icom radio through Trey is a great deal. I found the radio and GPS to be very helpful last year, but not 100% necessary. The radio is good for all of Trey's Raptor runs, and probably most other Raptor events.
I couldn't get my GPS to work for 50% of the first lap at TRR, but once I got it working it was very helpful. We only got off course once without the GPS, but easily got back on the trail. I now use the GPS for any trails we run in Colorado. It's a real lifesaver in my opinion.
I filled the gas tank on my Screw right before the event and carried a 5 gallon reserve. I never had to touch my reserve.