You can save a lot of cash if you do the install yourself. I recommend
Sound Deadening Materials for Noise Reduction from Second Skin and get the Damplifier pro and Luxury Liner pro. I've done the trunk and doors with this stuff and it makes a big difference when it comes to road noise.
The materials are pricey but installing yourself saves you in the end. You can probably do the trunk area and doors for less than $200 in materials. There's really nothing to it except taking apart the interior panels.