I am sure all that stuff will make a difference however be careful that what you hang overhead won't melt when the hot sun gets to it. In reading past posts on this subject that has been a real problem
If you want to go beyond just a difference to Lexus/LTD quiet there are several brands of vibration damping on the market at varying prices. If you do a search for testing in this subject you will find a website where someone did an unbiased test on 5 or 6 of these products. He came away from this test believing that a product called Second Skin was the best for the money. It is a thermal-acoustic vibration damper.
http://www.secondskinaudio.com/vibration-mat/damplifier-pro.php
