I've tried it as a "might-as-well". Didn't really notice much of a difference. If you look at the data they publish it doesn't really do much for temps with a 50-50 coolant mix: I'd assume most coolants already include surfactants to improve wetting. It's really designed for race cars running pure water, I think.
Note that it can react with some coolants to form a black goo that can make you think you blew a head gasket. Ask me how I know this.
I'm writing this in the hopes that it saves someone else a scare. I was working on the Spider and while checking my coolant found globs of black goo floating in the overflow tank. It being an Alfa my immediate thought was "#@%#$%! Another *&%$#@ blown head gasket!" The only thing I had done...
I might consider it if I had an overheating problem, but once my engine is up on temp, the gauge needle stays at high noon 175F regardless of ambient temperature or how hard I drive. Aren't all of our GTVs like that?