When it comes to sound deadening and such, I also really want to insulate from heat. I think a headliner would really solve that problem but I know it wont be cheap to get a custom headliner made around the roll cage tubes. Sound deadening does help with heat but is there a specific mat that is made to do both really well?
Once I get the bugs worked out I want to get carpet for the floor and a headliner, and even upholster/pad the roll cage tubes where the door bars are to use as an arm rest while driving since factory door panels will likely have to go for clearance issues.