What insulator should I use?

Okay so I have decided to remove the carpet from right behind my bench seat in my XJ. I know that if I leave it bare or just put herculiner down it will not be that good of an insulator. So I was wondering what I should put down to help eliminate noise and help keep it warm/cool in the cab.

I had read about someone using these in one of the threads:
http://www.b-quiet.com/ultimate.html
http://www.b-quiet.com/vcomp.html

but i am not too sure. Any suggestions? Oh yeah I am going to herculine over it b/c I use that back space much like a truck and my carpet is totally trashed.

I'd hunt around a boneyard for either some ex military hardware type trucks or regular DOD stuff, mostly they came with the rubber carpeting that has the jute backing or whatever they call it. Find one of the full size blazers and cut what you need to fit... The dealers also sell the rubber floor mat, they came in the police models and I even think I saw them on one of the vehicle carpet manufactures web sites, $150 for the whole thing comes to mind..

http://www.automotivecarpet.com/catalog/vinylfloors.php

i'd reccomend dynamat to reduce noise, but that's not only rather costly as a sound deadening material, you also can't put stuff ontop of it without messing it up. its best used when stuck to the floor then the carpet is put back down.
i'd look for the rubber flooring out of a fleet vehicle. i've seen them in XJs that aren't government use. junk yards in general seem to be flooded with XJs, so it shouldn't be super hard to find a set of flooring from one of those.

I just put down herculiner and pretty much forgot about it. I havent really noticed any different in heating or cooling with the carpet gone out of the back but I do have a small rug thats about the size of the floor back there.

AARON