I figured I would throw up a review of Liquid sound deadening sence I havent seen one yet.
Some pics will be at the bottom, seeing that the review is more important.

Product installed:
A (1)gallon of second skin spectrum liquid sound deadening. Cost was $65 USD including shipping.
It came in the mail to my door and it weighed appx 15 pounds. The consistency of the stuff is comparable to latex house paint.

Some thoughts after applying:
1.You need to prep the surface area well so I used windex then paint thinner. There is definately some time involved in that seeing that once you pull out carpet out of your trunk there could be years(and in my case 10 ) of dust and crap in there.

2. Plastic everything off you dont want to get ruined. Glass doesnt matter. This product doesnt run a whole lot unless you get alot on your brush, which is pretty easy to do. And when youre working on a trunk lid, its ever worse sence its near vertical. Wearing a hat would be Ideal too. Some how I dripped some onto my hair and didnt notice, but when it dried it was a bit(h to get out.

3. Multiple coats is better than fewer heavier ones It's easier to apply, and it dries faster between coats.. It also looks better when it dries.

4. Between coats takes about 30min-1hour.

5. 1 gallon is supposed to cover about 40 sqft. I think this is underrated. I wasnt stingy with each layer. I put 5 coats on my trunk lid, and covered my whole trunk in 3. I drive a boat of a car, so there was well more than 40sqft there.

Overall after I got the deadening put in I didnt drive my car for about a day. When I cranked it up to test for some rattles I found that most of the minor areas were taken care of, and the one major one was less noticible. 1 new rattle showed up which was my keyhole cover, but thats an easy fix. Dries pretty smooth too. Time spent including prepping and waiting between coats 4 hours and change.

Overall : 4/5
Ease of use 3/5
Value: 4/5

I would recomend this product :thumbsup
Any questions/comments shoot me a PM.

Now for pics:

This is after I cleaned the lid:

After 2 layers, still drying in the center of the pannels

And the main part of the trunk floor, still very wet.