Apart from noise I think it will make a big difference to summer heat.
On the last trip to the Pilbara, I noted that with the windows up and the A/C on the cab cooled a bit, but as soon as the windows were wound down, I could feel hot air rushing in through the seat box, like it was being sucked in by a venturi effect. The parts of the seatbox that were bare metal were hot (not burning) to touch.
Without a radiator battling my A/C, I think I should get cooler A/C. The problem with the Defender's A/C is not the temp, as it gets very cold, but that the fan speed doesn't match the internal volume of the vehicle, which means the back doesn't feel cool in hot weather, even though the front passenger is freezing.
I've also ordered the new door seals that fit on the bottom of the doors and come up in a U shape. That will allow me to remove the seal on the floor, and make sweeping out the floor a lot easier, as well as sealing the door better.

