Basically there are 3 basic commonly used products for sound insulation, and most manufactures produce a variant on the same theme.
1) Vibration dampeners - These are typically made of butyl rubber or asphalt based products with a constraining layer which is typically aluminum. The ideal setup is for the constraining layer to be the same thickness and material as the underlying panel that you are trying do deaden the resonance in. For practical reasons most companies simply use aluminum because it is light, cheap, and readily available. I would AVOID asphalt based products because they have a tendency to smell, and can melt and seep out. But most companies now seem to have moved to the butyl rubber products now anyway.
2) Foams open/closed/mixed open closed varieties - These work well for several things, they help tremendously with helping your AC work better (and heat if you have to live somewhere cold
), but from a sound perspective they work really well for high frequency sounds and as decouplers to prevent direct mechanical sound transmission from a panel to the mass loaded vinyl (MLV) to help the MLV work more efficiently. Best thing about foams is they are light, the bad thing is that for low frequency sounds they are not very efficient at all.
3) Mass loaded vinyl - This is the major work horse in sound deadening. The downside is that it is heavy, but it has to be to work. The thicker and denser (i.e. heavier) it is the greater the ability do deaden sound. This will knock out sound pretty much across the spectrum.
These are the only ones I'm going to detail here but there are some other products that have variable properties for different applications, and if you want to look them up there are coatings, foils, and heat shielding products that can help. Probably the only real relevant one is a good heat shield with sound isolation properties if you are willing to do some real off-clam work.
Also, some products combine more than one of these such as Luxury Liner Pro which is a MLV and foam decoupler.
So with this background we can look at each of these products you listed.
is basically a butyl rubber product with an overlying foil, just based on the description this sounds a lot like your typical dampener material similar to damplifier and dynamat extreme. Unfortunately on their site I do not see the thickness of the constraining layer (foil) specified, so it is hard to compare directly to the others. Basically thicker butyl and thicker foil = more efficient but more weight.
This is essentially the exact same as the E-Dead 45, but it is just thicker 80 mil instead of 45....So as above thicker = more efficient but heaver.
eDead v4 - TekLite
is a neoprene closed cell foam, which is basically like overkill foam or dynaliner. Note that this is only foam, no MLV. This can be great for a lot of applications such as doing your doors, wheel arch liners, dashboard, etc...
I do not see any product that this company offers that has MLV incorporated into it, and they do not have a separate MLV product. I would strongly urge you to use an MLV based product at least on the firewall and bulkhead, as you will lose a huge amount of efficiency without it. For everything else you could get away using the eDead v4 - TekLite foam probably. See the first post for how to use the dampener products, they really have a specific application for which they work best.
A couple of things to consider. First, adding any sort of mass will have sound deadening properties, but the goal is really efficiency for weight. That is why I recommend the Dampener covering the center 25% percent of the panel (which gives you the most bang for added weight) - with foam decoupler overtop - with MLV on top. There are several products that incorporate the decoupling foam and MLV into one.
Another thing to consider with sound products is that they are heavy, and some companies will try and make significant profit on their shipping to make up for lower "cost" on their products, so make sure the shipping is reasonable. Remember this stuff is on the bigger and heavier side so shipping of 20-30 would probably be what you should expect.
I don't know if it would be more cost effective or not, but another place to look for products is home theater supply companies...I don't mean the stores that sell electronics, I mean the ones that install movie theaters in houses or other places. Guess what they use in the walls to isolate the sounds.....Decoupler foam and a MLV. You may not be able to buy small quantities, but if you can the cost will likely be much less I would expect as the car based companies are expecting low volume purchase and their prices reflect that.