I left the cab vents on the back wall exposed in case I drive off a cliff into the ocean? Or get trapped in tunnel? I don't know why they are there, but Ford put them there, so I guess they are there for a reason. The 'gtMat' (economy Dynamat) actually works well. I can tell a big difference with sound coming from the back. But even if the noise from the cab vents gets too loud, fortunately for me, pioneer installed a volume **** with my radio specifically to drown out cab vent noise. Your radio might have one too, just in case you want an alternative to rolling down all the windows. Just sayin.

 

any amp over heating problem with it behind the seat?

 

No overheating problems. Maybe the cabin vents keep it cool.