Well, five (5) liquid gallons weigh eight (8) pounds per gallon. I just wieghed a gallon of water.
That makes forty (40) pounds of Quitcoat total. While wet. Once dry, the weight would drop significantly. Call it thirty (30) pounds of Quietcoat.
(BTW, I purchased, and
won't be using, one-hundred (100) pounds of eDead. A mat-type sound deadener. Sixty (60) or seventy (70) pounds would do a
hell of a job in a compact car. Tops.)
The Foamseal should wiegh about fifteen (15) pounds. It's foam.
I also added in an IKEA brace, call that another five (5) pounds.
Lost my sunroof, that I hated. Call that a loss of twenty-five (25) pounds off the very highest point in the vehicle.
Bought a PC-680T battery. Another twenty (20) pounds off the front end of my vehicle. Another horrible place in the front-wheel-drive vehicle for weight.
I am removing the crappy tar-like OEM sound deadener. A loss of another ten or fifteen (10-15) or more pounds.
Therefore, I am adding about fifty (50) pounds worth of chassis stiffener and noise reduction.
I have purposefully deleted sixty (60) pounds of weight.
Seems to me like my vehicle will be waaaaaay stiffer and quieter than OEM. With a zero (0) weight penalty. In actuality, a simple to acheive
reduction of ten (10) pounds. This result, along with better weight distribution, when you look at my
overall build.
Even if you factor in an extra ten (10) pounds over stock for the (planned) upgraded, high-quality, yet modest stereo (new headunit drives the four new mid-hi's, small self-powered subwoofer) system, I am
still at about break-even on the weight.
Further, this is a daily-driver first and foremost. I plan on it excelling in
every respect over the B13 in factory trim. That means
every facet of performance, including daily comfort levels, NVH reduction, and a better sounding stereo.
You are correct, the benefits of the chassis foam and sound deadening
far outweigh any neglible weight penalties.