that the rear wheel wells are not metal or plastic ladened as normal, but rather they have this felt cloth type material lining them a la audi. audi has been doing this for years and i love that they do. it reduces many different road noises(driving in rainy weather, rocks skipping inside your wheel well) and just makes driving so much more enjoyable because of it. i'm glad infinit has decided to use this simple technology.

It certainly feels like felt, but I bet it is something much more durable.

The main use of it is to prevent water splashing out and obstruction other drivers views due to being splashed. The other use is it insulates from sound better than plastic.

Yes, this is common now in a lot of cars--my old TL had it.

Yea I also Noticed this Felt Looking material collects alot of road debris on it! Like leaves, grass, etc.....thats what happened to mine after a night of rain going home. next morning i used a small Bristle Brush to take those thing off. As it just looked Unsightly having all that stuff stuck in the Wheel wells! Just my 2 cents

Well, love the benefits but wonder about its ability to collect more debris or whatever the road throw at it.
Will my car get heavier by time because of this?

haha. during my time working at the detail shop, i had a number of audis come in and all i found that the felt material picked up was minute sand particles and such. as long as you wash out your wheel wells, everything should be alright.

Is there a way to retro this to older cars for the sound benefits? What kind of material is it actually?