I am looking at insulating my garage door (in LA so I am worried about heat and less about cold). Looking at an R5 and an R8 solution. R8 would run about $140. R5 about $85. I am thinking it would take a LOT of heat savings to pay back that$60 or am I way off base?

There are a lot a variables; do you heat or cool your garage? If so what is the temperature differential? Does the garage door have any insulation now? Are you better off spending the money on another part of the garage? How is the garage built?