Before I tore it apart, my car was the same as roadking, couldn't even hear the radio over all the noise. So my goal is to install the most soundproofing possible but without spending a fortune. When I first started researching this topic I found it hard to figure out what to get based on the marketing.
I found that these sources were the most informative.
https://www.sounddeadenershowdown.com/http://www.myturbodiesel.com/wiki/soundproof-car-diy-to-reduce-noise/https://www.youtube.com/watch?v=I5E9mjI3y1EI've yet to find a good example of someone who measured before and after with an audio meter, although the video above comes close.
Your link is for the RAAMmat BXT II which is a stick-on butyl rubber (for deadening vibration and resonance) and aluminum foil (for heat) with a second product of foam that you stick on top of the butyl. For the most effectiveness you still want a third layer that doesn't stick on, just lays on top, of mass loaded material (for noise). This is typically a vinyl but you can also purchase a carpet kit for your car that includes the mass loaded layer. Keep in mind these products, except for the foam, will add quite a bit of extra weight. The butyl rubber and mass loaded vinyl can each add up to a pound per sq ft of material used.
I've only bought (not installed yet) the butyl/aluminum sound deadening layer. When I researched it last year I compared Dynamat, Summit brand, RAAMmat BXTII, Stinger, Fatmat, and Noico. The least expensive per sq ft was Noico by a considerable margin, with Dynamat the most expensive (the list is in order of cost). They all have equivalent product as far as I can tell, but when you compare make sure to look at the thickness/weight of each product. I've yet to purchase the foam/MLV layer(s) but looking at either a single product that combines both, or buying just the closed cell foam and a new mass loaded carpet kit.