Doghouse Noise and Heat

[Pubtym]

I have a 2006 Winnie with 8.1 Vortec engine with 12000 miles on the rig. At about 62-65 mph a fairly loud Allisson tranny whine can be heard through the doghouse over the engine and tranny. In summer, I have also notes a noticeable amount of heat radiating off the carpet covering the doghouse.
When I opened the doghouse today, I found little to none sound insulation material...just a thin layer on metal reflective sheeting.

Question: Has any one installed any added sound-heat barrier material along the under/interior of the doghouse to reduce radiated noise and heat?

http://www.b-quiet.com/ultimate.html