[John U]

Front wheelwell liners, Yes! They are like an echo chamber

Did one side, need to do the other side. I apply an adhesive backed "acoustical foam" to the back of the plastic liners and the stiffer Siless type product to the firewall. I need to pull back the carpet and apply there next.

 

[John U]

how did you remove the wheel well liners by yourself ?

Remove the tire, remove the 5ish screws along the bottom and up the side of the fender. Remove the 3 round headed anchors on the fender holding the liner. Pry the heads out of the 3 "push pin" retainers scattered around inside of the liner and pull the liner down. I only removed the rear of the liner, leaving the front half attached. You have plenty of room to work in there.

 

[John U]

I don't think that these products are meant to be used on exterior panels as water could get trapped behind them. I would look more into that first.

The liners are no rust plastic. I've used a similar formable foam product for ten years on a Corvette and recently removed the liners to add another layer, only adverse affect was a little road dust to blow off. Yes, the second layer was worth doing!