My 2005 Civic 4-door is has a high level of road noise on the highway and I am looking at putting in some noise dampening material. A lot of the roads I drive on are "seal coat" (gravel poured over a tar-like base and then worked in by the traffic). Also, I believe the OEM tires that came with the car add to the noise level. I am looking for suggestions on where to place those noise dampening sheets for maximum effect. Has anyone out there already done it on this generation of Civic? Thanks, Mike