It's amazing just how well it lowers the noise when it weighs almost nothing and isn't THAT thick lol. I had it out for a day while I was working on something and had to take it to work before putting it back.. Man, that was awful. It's one thing if it's engine noise.. but the road noise... no thanks.
A drive around the block was enough for me too. The sound of everything hitting in the wheelwells was crazy.