You can do that. It will reduce tire/road noise. Lexus and other higher end vehicles apply sound deadening liners on the back of the fender liners in front and on top of wheel-housing in the back trunk/hatch. For example, my ES had felt-like material in the front and foamy material in the trunk...

 

So you think taking down the liner and applying noico 80mil to the backside of the liner would make a difference? Or take liner out and apply to car and backside of liner?

 

Noise insulation in the wheel wells might also lead to premature corrosion. VW put foam blocks inside the wheel wells on TDI diesels to reduce noise. I worked, but the foam would accumulate moisture and grit and rub against the metal bodywork. The result was corrosion and perforation. Fortunately at the time VW had a 12 year corrosion warranty (now reduced to 7 years) and both front fenders on my affected car, a 2005 Passat TDI, were replaced under warranty. Jettas TDIs also had an issue with this and I believe VW had a TSB about it.

My 2020 SE sedan is definitely noisier (road, engine) than my 2018 Golf Sportwagen. I've just accepted that "it is what it is". Since we carry gear when we travel (bikes and stuff), our Sportwagen will remain our road trip car, so I don't really care on the 100 km max drives I do in the Corolla.

 

I just checked mine and maybe an XSE thing, but my rears are felt lined.

 

Felt lined on the inner side that you can only see when removed?

 

Nope. On the outside. Really is a dirt collector...

 

Nope. On the outside. Really is a dirt collector... View attachment 382209

Just checked mine and mine on the rears are in fact felt but fronts are just plastic. Maybe that's why I'm hearing it from up front and not the rears. Not the best pic but this is the plastic on fronts

 

I ordered some kilmat. Gonna stick some on the front liners on the firewall side and maybe on the metal skin in there while I'm there