Neil, I lined the footwell, floor, sides and back if the passenger compartment on the Roadster.
Dynamat Xtreem does exactly as it says, the reduction in noise and heat was significant, even without the Dynaliner.
Fitting it is tedious and you need a lot of new Stanly Knife blades as the backing is quit thick, soft aluminium sheet. The stuff is also very sticky, once fitted it isn't easy to remove! Measure twice and cut once and make templates from card where needed.
There is a thread here with details. I'll see if I can past a link to it.
I suspect it would help a lot in the M3W, but I'd add the Dynaliner on the floor and rear bulkhead.
