How many have under coated their car? We live on the coast ,but did not under coat the car, I did however get some do it yourself spray for the rear wheel wells and it made a difference in noise level coming from the tires on the rougher roads. Also I feel better now as looking at the grey matter in the fender wells now looks better black, I think.

 

I sprayed my rear wheel wells also. Couldn't believe that the open weave would hold up to winter in the Northeast.

 

The rear fender liner material has been used for years on Mazda6 with good success. I'm not worried about it at all.

No aftermarket undercoating needed in CA.

 

Wasn't to worried about the liner falling apart just wanted to cut down the road noise and it did make a difference.

 

Good to know (even if the difference in road noise is small, since most tire noise is tranmitted into body through suspension mounting points).

 

I don't have experience with this stuff but it is interesting:
Noise Damping Technology for Cars, SUVs, Trucks, RVs, and Other Vehicles
I did use a noise insulation mat under the hood of a Ford Contour, 2L. and that helped a lot with this noisy engine.( NAPA, $50, special ordered).

Let us know what you do and how it works.
I test drove a '10 Chevrolet Malibu , 4 cyl and that is one quiet running car!

 

I hate quiet cars!
Ever think the car isn't running and you accidentally try to re-start it--------followed by grinding noise.
I doubt i'll ever by electrical!
I am still waiting for a proper electric car with a very small back up engine used to just drive a charging alternator like the size of a Honda generator.
The Chevy Volt engine is way to big: 1.4 litre.