I don't know if it lowers temp but I'd guess not as the T'stat regulates that. I use WW in the instructions on the bottle. I ride all summer in AZ and I figure it couldn't hurt.
I was under the impression that once an engine reached a certain temp during warm-up the thermostat just opened up and stayed that way until the engine was shut down and it cooled off.
As far as WaterWetter is concerned, it is not an antifreeze, it is works like a surfactant, causing a reduction in the surface tension of water. Circulating coolant, including water comes in contact with heated internal engine parts and actually even boils at the hottest areas. Breaking the surface tension results in smaller boiling bubbles and more efficient heat transfer.
It is also my understanding that water is a much better heat transfer medium than glycol. The advantage of antifreeze is it has a higher boiling point and a lower freezing temperature. An engine can actually run cooler with water than antifreeze, which is the reason race cars use water treated with WaterWetter in their applications.
Here's what they claim:
ABOUT RED LINE WATERWETTER® COOLANT ADDITIVES
Reduces or eliminates bubbles or vapor barrier that form on hot metal surfaces to reduce coolant temperatures by up to 20°
Superior heat transfer properties compared to glycol-based antifreeze
Compatible with new or used antifreeze (including DEX-COOL and long-life versions) to improve the heat transfer of ethylene and propylene glycol systems
Improves heat transfer and reduces cylinder head temperature
Designed for use with all modern aluminum, cast iron, copper, brass and bronze cooling systems
Cleans and lubricates water pump seals
Reduces cavitation and complexes with hard water to reduce scaling
Does not lower cooling system below the thermostatically-controlled temperature
