Have a look here mate...
http://teamspb.co.uk/TEMPLATE/secondskin.html all depends on what you want to do to be honest...
If you want to quieten down the car, then you want to put a layer of deadening (second skin, Skinz, Dynamat, Silent Coat etc) down, then you can put a layer of an accoustic closed cell foam which will help stop the airbourne noises...something like the Second Skin Luxury Liner/Pro, Second Skin Overkill etc...then get your original (buy one) carpet to fit over the products...
If you want to go crazy, then add
http://www.carpet-underlay-shop.co.u...07-m2-25-p.asp before the carpet goes on!
bassboy