2010 Honda Fit Sound Deadening Project

The Honda Fit, like many smaller cars, is loud in the cabin. Road noise is harsh, and in ETX, made worse by the surface of some roads.
I didn't want to tear everything apart and try to reduce noise. I didn't have the time and didn't want to buy that much sound deadening material. I got 18 Square Feet of 80 mil Kilmat. Will it make a difference? Will it be a waste of time and effort?
Install Areas:
Front Floor Mat Area
Rear Axle/Wheel Well
Hatch/Trunk Area
18 Square feet doesn't cover 100% of these spaces, but it covered a good bit of it. Sounds deadener is 80 mill Butyl and Foil material. Self adhesive.
The DB meter is a free app off the Apple Store. I doubt it will be specifically accurate, but I hope it is consistent from pre to post deadening.
As you watch, you will notice that the mount I was using for the pre- recording is different from the post- recording. The mount broke in between videos. An iPhone XR has mics on the front and bottom. The old mount had a hole in the bottom to let cables and audio through. So, the post- recording is still similar, though somewhat more open to the mics. If anything, this makes the DB meter more sensitive, and puts the post- deadened audio at a disadvantage. but I don't think it had much impact, over all.