I don't think it makes a whole lot of difference. Maybe it does at 85+ MPH, but I don't typically drive that fast.
As
@StealthP3D pointed out the bulk of the noise comes through the frame from the tires hitting the road.
A ton depends on the road surface you are on and the speed you travel at over that surface.
There is so many "noises" entering the cabin at different frequencies from different sources and getting through different paths it's hard to pin point the effect of any one change.
I've done the RPM Gasket, Tires, Cabin Mats, Trunk Mat, Lower Trunk Mat, Frunk Mat, Stuffed Frunk, Both Front and Rear Sun Screens (probably my favorite noise mod), DIY Door Gaskets.
I'd say it's 30% better (on 80% of the roads and not exceeding 65 mph).
But certain roads at high speeds still sound like roaring thunder.
The car lacks acoustic glass (and it has more glass than most cars), and lacks insulation in many parts of the vehicle.
Sometimes when cars pass me on the highway I think my window is open that I can hear them so clearly.