"Part" of it is true, the difference between 350w and 500w is less of an impact than just the addition of more speakers. To get 3dB more than 350w you need to go up to 700w, but adding that 15" is about another 3dB on its own, plus maybe another 1.5dB from the extra 150w. The second cab makes the bigger part of the difference vs just the 4ohm wattage bump. And the fact that the combo is raised off the ground.
I like the 112 cab myself, the 115 doesent fit in the back of the car, and triggers "gotta turn one sideways" ocd, as well as added boom, but the boom is wanted by many, so I can't knock it.
The ocd and compactness, and lucking out to get one from @honeyiscool semi locally, led me to the 112. Been very happy with the sound, it is almost like having another 115 in the combo size box sound wise... Almost. But it balances perfectly probably because of the low mounted ports, and fact that it is coupled to the ground while the 15 is raised up. Best stand for a 200 or 500 that money can buy in my opinion.View attachment 1148939
That looks like my trunk. LOl I have the 2x10 combo with the 1x12 cab.

