you would have to take into consideration that different area of the car requires different products (thickness / density) to work best for the area...

a rough idea for you to estimate, a normal sedan(vios/almera/city) cabin full sound proof including the rear trunk area... would take total of 60 pcs of sound proof of various series...

and to your expectations...
it kills the rains noise other than those coming from the windshields..
it kills the road noise coming from the floor pans...
it helps on the audio tremendously...
thats about it to my honest opinion...

but to really reduce the NVH levels when cruising, consider sound proofing and then auto foam your car chassis... that way the wind sound that travels through these tunnels are completely removed and its really quiet during high way speed...

and it comes down to your engine, tyres and suspensions...

so...

craziechild is right, he dint mean u need opt for various brand

yes you can stick to 1 brand.. but there is different tpye of product in a brand...
dynamat have product specialize for hood which is hoodliner
for thermal insulator which is dynaliner

so if roof u wanted to reduce heat n sound, stick a layer of dynamat extreme n another layer of dynaliner... this is what craziechild mean, BTW sorry ya if i explain wrong dont flame bro.

actually personally, this is just my personal thoughts la,
just get stp or dynamat stick 1 layer kaotim...
no need opt for so many layer de la... going for competition meh....
so many layer d car damn heavy wei...

front door, firewall, front floor..agak-agak je la