How much weight are you going to be adding??? I do not notice enough road noise to bother me ... if it does I turn up the radio. From everything I have read it is quieter than most car in its class. Did you change tires and wheels?
Just curious why you want to do this…. Most of the noise in the G that bothers me is wind noise. How would you attack that?
Where you are planning to add the material you should not have a problem with radio reception or keyless entry.
The install shouldn't add more than 30-40 lbs to the vehicle. I've found that removing the seats will require a visit to the dealer (to turn off the airbag light), so I'll stay away from the floor pan for now.
I agree that the G35 is a quiet car, but its interior noise and vibration levels lack refinement on rough roads. This is especially true when compared to a lexus gs300.
I'm not sure about the wind noise issue, as glass is transparent to sound, and airstream manipulation over the windshield is beyond me.
The lead sheets I intend to use are only 1/64" thick, but weigh a pound per square foot. Lead's noise/vibration attenuation is apparently superb. I will soon find out.
Why lead? [img]/w3timages/icons/crazy.gif[/img] Though it may be reasonably good for sound attenuation, I'm not sure if it's any better than material like 'dynamat' which is specifically designed to control sound.
Might be good for the times that you run over Kryptonite though! [img]/w3timages/icons/wink.gif[/img]