Gumout Fuel Injection cleaner is ACETONE...
You probably meant to say Chemtool Fuel Additive and not Gumout. Gumout has several on the market and they all are petroleum based, not keytone based. Gumout with Regane is one of the best out there with Polyether Amine as the active ingredient. PEAs are in a lot of the better fuel cleaners as well as Stoddard Solvent types like BG44 or some of the Techrons. The Regane cost a small fraction of the others though and works just as good.
As you stated, acetone is also a plasticizer and can do damage to the plastic parts of the fuel system. It also is a great paint remover so getting any on the side of the truck certainly won't help the paint. As far as acetone relieving surface tension, in the lab it's possible but not in your fuel system. Any gains that folks "feel" from the use of it is probably that it is an almost instant solvent and it can clean a fuel system quick. Obviously, a clean fuel system and injection system is going to run better. Although acetone has a much higher octane rating, about 140, you'd need to add gallons to your fuel tank to effectually raise the octane level of the fuel in the tank. Adding 8 oz of acetone to a gas tank of 25 gallons (which is also 3200 oz) is not going to do much if anything to the fuel. The percentages just aren't in it's favor.
In regards to your comments about 87 gas burning hotter. There are about 119,000 btus in 87 octane gas. A 93 octane gas has about 127,000 btus. While theoretically the higher octane fuel has more energy in it, unless the engine is designed to use that octane level, it is wasted energy in an engine designed for 87.
While we are approaching this from different angles, I think we're beating the same horse with different sticks.