Insulating a diamond plate floor?

[EDNY]

My main floor section is approx 4'x4' (11 ga) aluminum diamond plate. Don't want carpeting and may even make the coupe door panels out of the same diamond plate.

I can sound proof/insulate the rear trunk, tubs and door panels from the inside no problem. Looking for any ideas for insulating the floor from the bottom...ie spray on, glue on etc 

While I have no intentions of removing it on a regular basis after it's riveted down...the aluminum floor can be removed by taking off the passenger door.  Don't want anything super thick, the exhaust will be approx 8" below the floor.

Ed

[EDNY]

Never mind...JC Whitney had a sale on the sound/heat insulator rolls...just ordered one. Will use some 3M adhesive and will be good to go!