Another Rhino Liner Question

[gavman]

I had wet carpet in my truck so I stripped out the carpets and bits from my Hilux today and the cab is in a very rust free good condition.
I want to Rhino line it.
I am a bit concerned with sound and want to get the most bang for my buck so I am thinking of applying the product that custom speaker shops use for sound deadening (B-Quiet sound deadening materials - B-Quiet Extreme).
My question is can I apply the Rhino liner over this product or should I Rhino line first, then this product and Rhino line again to seal the deal.
Will the Rhino stick to a product like this?

And another question, There is currently a hard but brittle coating in some areas of the truck that can be removed cleanly but to do so is a fairly big job. Have you guys removed this or just covered over it?
Sorry don't know what it's called.

 

[fieldsken1]

if you dont have a good surface for the linning it wont stick either it is only as good as the surface you put it on

 

[1loudLX]

I would try to clean up the surface as much as possible and only rhino to the metal. I would not put rhino on top of sound deadening material. If you're truely concerned stick the sound deadening material on afterwards, but I wouldnt put another coat of rhino on top of that. If it was up to me, I would rhino it once, let it cure and harden and probably do another coat. The stuff basically works as a sound deadening material itself, so if you build it up in thickness it should reduce noise.