Bashful Insulation

There is an insulation product available in Australia called "Aircell" - it is mainly used in commercial building roofs and has about the same insulating ability as 3 inch fibreglass roof bats. The Aircell material looks like plastic bubble wrap, but is about half inch thick. As it is relatively easy to get as scrap from building sites (and thus very cheap), has anyone used this or similar product to insulate cabin firewall (for coupe particularly)? If so, how effective? How did you attach without glue so that it could be removed if necessary? Did it also stop some of the engine noise? (And a thousand other questions). Hope this is not a bashful question.

Generally, thermal insulation does not make good sound insulation and vice-versa. Not to say there can be a compromise between the two, but thermal insulation is by nature low density material, wheresas acoustic insulation is os relatively high density. I think most of the insulations you see marketed specifically for cars is higher density which will give you somewhat of a thermal barrier, just not as much as building thermal insulation. The car products are usually aimed primarily at noise reduction.

You mean something like this 1/4" product:
cut:
http://picasaweb.google.com/bmcautos/1958MGATwoPlusTwo/photo#5213487806839852578

full picture:
http://picasaweb.google.com/bmcautos/1958MGATwoPlusTwo/photo#5213487638019754850

Installed:
http://picasaweb.google.com/bmcautos/1958MGATwoPlusTwo/photo#5213487515733908498

painted:
http://picasaweb.google.com/bmcautos/1958MGATwoPlusTwo/photo#5213495414379602706

I think it helps. I didn't really have authorization to spend gobs of time and money on sound deadening and heat resistance so I purchased this inexpensive product because everyone said that MGAs were notorious for firewall and cowl heat. I didn't want the car to be miserable to drive when finished so figured this is the least we could do. The only thing i question is whether the paint will sick to it over the next few years or not.

-BMC.