Ziay!

sunfishy

I have a 2001 civic, but on highways at high speeds it is really loud inside the car. I googled for soundproof car, but couldn't find much helpful info - how much might it cost? what kind of car place would do it (body shop, repair shop, ?)?

cantstandya

Go to a car stereo shop. The reason you would go there is because sound dampening is part of high end car audio systems. The last thing you want is road noise on your expensive car audio system.

There are items you can buy such as spray on material, adhesive pads, and non-adhesive fabric type material. Dynamat is the big popular provider of sound dampening materials, but there are online places like partsexpress.com which will sell you cheaper no-name dampening material. Just look it up in their car-audio section.

You will likely find that decreasing the noise is gonna cost you a good chunk of change and a lot of work. Usually you need to 'dampen' (add sound deadening material) the doors and floor. You can also do the roof if that is the main source of your problem. If you are a DIY'er it can all be done for a few hundred dollars assuming you are comfortable with disassemblign your cars interior parts. I would let a pro do this as there is too much potential to break panels and improperly install the materials.