I used the Noico stuff for sound deadening. I also insulated the center console, and added a bit of rubber hose around the shift lever and some foam under the shift pattern cap-it was pointing directly at my right ear and was entirely annoying. Most of your noise and heat is coming from the transmission and the firewall, so insulate as high up the firewall as you can. The doors are noisy as well, but I didn't want to add the weight to the doors. I wasn't really insulating for heat, just noise, though I did replace the carpet with the heaviest mass backing I could get (ACC carpets).
Each product has a decent online tutorial vid to help you with the install. This is the perfect time to do it-not too cold, and not hot or humid.