Take a look back where all this started at my post #1, it is ALL documented there. BTW I think you are referring to the wiper motor cover. Also, it's heat soak into the evaporator enclosure.
I just finished wrapping the flexible air hose. It is a tight fit, but you can detach the two screws from the blower motor cover (black cover with the fuse box on it) to help with making room to get it back in once wrapped. While the cover will not come off due to a zip tie holding it on, it gives enough clearance to get the covered tube back in. I also think the covering of the tube will have the added benefit of acting as a further barrier to heat from the master cylinder and other brake parts on that side of the car.
Michael, can you tell me some of the specific additional areas that your insulated? While I have it cracked apart, I want to get it all done at once. You mentioned that the goal is to prevent heat soak in the heater matrix, where is that located? Is it the part that the lower cabin air tube connects into?
Now I just need to experience the fruits of my labors!! Cooler air here I come!!