This has been a challenging adventure, how to make a great car more comfortable to live with yet keep the dynamics of the car intact.
The reason I wrote the new guide is to specifically address these issues, go after the main problem areas first, once you get to a point within your noise tolerance level then stop. Many have different levels they are willing to give up and what they need to gain so you have options to help address this.
As for liquid deadeners, I have tried quite a few and have looking into having my own but nothing has impressed me that well yet. Liquids seem a great way to go but you also have alot more prep to prevent messes that are hard to clean up, many require alot of coats to build up a thick enough layer to be effective, lack the aluminum layer that helps stiffen the panels(much more so than it may seem they would when using multiple layers), etc. There are other issues as well with this method, the only real gain I have found is nice to be able to get it into some areas hard to reach by hand for a mat type product. Then again, spray on is best for that and I have tried alot of them, so far simply not cost effective. I will keep looking into this though, just may come up with something good.