i'd like some advice about how i can improve the sound of the stereo in my 1983 300D turbo.

i've got a clarion cd deck, 2 4" jensens in the front, 2 5.25" infinity reference in the rear, a 12" infinity reference sub in a sealed enclosure firing up towards the hole in the rear dash where the medkit used to be, and a 700 watt 5 channel hifonics amplifier powering all the speakers and the sub.

it sounds pretty good, but i feel like it could be a lot better. the bass sounds a bit muddy, and i don't think i've nailed the crossover points yet.

i want to reduce the road noise, but i want to be economical about it. how much would time and money would it take to lay down dynamat (or the roofing-supply equivalent i've heard so much about) on the floor of my car? how much would this help with the road noise?

i welcome your suggestions!

if your car is anything like mine (79 300sd) the trunk is soundproof. (except for that med box) so although it can come it. well most won't. i cut open a hole in the rear deck, sound proof the trunk. and u need to play a test cd toi find out what frequencies sound good, uhh i think it is something like a resonating frequency every car is different, or so i heard.. anyways go to sound domain.com and search for the s-classes in the member page, i think mine is 2nd from the top.. srry i am too lazy to go look up the url.