Sound deadening needed more on pass side?

[blackbetty14]

I did my JBA catback which sounds great and had purchased this Siless 2 in 1 prior to the catback purchase when I still had my borla muffler swap on the truck. Before the JBA was even a thought I figured covering the rear wall and under the seats would cut out any resonance I was getting. So today I decided to tackle this before it gets too cold out and I will be driving more with the windows up. I covered 90% of the rear wall and then went down under the seats to the storage areas and I was still able to get my subs back in. If it quiets the cab more I’m good with that and if it helps with added bass that’s a bonus. With the borla I was getting “resonance” slightly and it always sounded like it was coming from the back wall behind me on the driver side. So my question is I figured the pass side above the muffler would be more important and I should continue down? I really didn’t want to continue tearing everything up to do this if it’s not going to noticeably benefit. I used slightly less than 1/2 the box of 36sqft so at max I might have enough to do right up to the back of the front seats.

The deadening I chose was Siless professional 2 in 1 and it’s 157mil thick with about .050 butyl mastic and then 100mil of closed cell foam. I did the Siless 3 in 1 in my firebird this winter and it made a huge difference inside but I did 100% of the floor throughout. The 3 in 1 is the same but uses another layer of foam and foil top.

Thoughts on continuing or am I at diminishing returns if I’m not planning to do the entire cab?