Pontiac Owners Club UK

What's a good underlay insulation stuff for putting under the carpet? Mine still had the original fibre stuff that looks like asbestos, but it's got soaked and is going mouldy, so just needs to be ripped out. I've already put sound deadening stuff down but an extra layer of insulation would be nice as well.

I'm also going to need the black plastic covered insulation behind the pedals and dashboard. That's soaked as well and I'm going to have to cut it out to get to the big rusty hole behind it