I did this along with insulating all of my interior panels. It was a lot of work but it was worth it. But a lot of heat still came up from the cat through the rear rack and would get into the cab. I now have a full Muzzy system (no cat) and it made a massive difference in the heat back there as well as what was coming into the cab. No heat issues whatsoever now. I honestly think the header wrap and cat delete would be sufficient had I known how much heat the cat was generating.