[DanEC]

I'm sure I've gone overboard but I used a thin (.040) mastic sound deadning mat over the entire interior and Cool Mat on the floors and tunnel, inside of footwells and inside firewall. Also Lizard Skin on the underside. But, I have underfloor exhaust. I used the mastic to deaden any noise and vibration from the aluminum panels. I plan to do the floor of the trunk with the .040 mat just to make sure that "big" flat trunk panel stays quiet. Without side exhaust or solid lifters I won't have as much engine noise to mask vibration and panel noise.

Just from test starting my car and running it at idle for about 5 minutes last week I noticed the floors were already pretty warm and that is after ceramic coated exhaust, Lizard Skin, B-Quiet mat and Cool Mat on top.

With side exhaust you probably wouldn't need (or want) as much as I put in. I'm probably going to be hauling about 50 lbs of sound deadner and insulation around but I'm not building the car to have the fastest, baddest boy racer around.