anyone stick the bitumen on the firewall, at the engine side before?what is the effect for sound proofing ?is it noticable?bcoz at 1st i tot wanna open up the dash and put bitumen+superlon...but dare not to kacau the dash since it may create more problem after i open up. so now change my mind to stick on the engine side firewall, but before i do this, can anyone tell me the bitumen can last or not?with the engine bay heat...will it peel of?and is it will help in sound proofing?thanks yea...