Dont see how it would slow the burn that much, but water/meth will obvious cooli9ng benefits everywhere, and more efficient usage
And by sounds of it and a verbal description I was given about Power Pour...it does slow the burn, hence allowing more timing.

Although it does seem to come reccomended by very reputable tuners, so I'm sure they dont say its good without good reason.

http://www.webster-race-engineering.co.uk/powerpour.htm


It would be good to see some independant tests with say SUL + power pour, and SUL and water/meth injection.