Dynamat on Firewall, Inside Cabin or Engine Bay? Options

[andys]

I've seen people put Dynamat (or similar product) on either the cabin side or the engine bay side of the firewall (or perhaps both sides?). I'm thinking the most effective placement is in the engine bay, as it will both reflect heat and dampen sound where as in the cabin it will primarily dampen the sound but the firewall itself will not be isolated from absorbing heat.

From a strictly cosmetic standpoint, there's nothing quite as nice looking as a freshly painted firewall, though the "Dynamat look" is kinda cool too. I'm doing a V8 conversion, but the principles should apply either way. I'm near the high desert in SoCal, so heat management is an important consideration in these parts.

Andys