The reason that hot rodders used to run cooler thermostats in their cars (Mustangs come to mind) is that in the pre-DIS days, you could gain ~10 hp by running a cooler thermostat, bumping the ignition timing (since with a cooler engine, the fuel charge was not as likely to detonate) and running premium gas. Our cars have a DIS system, and hence you cannot change the base ignition timing setting unless you use a computer chip....
Hell, I ran a 160 degree stat with ~19 degrees advance base timing on my 88 GT for a while w/ preminum gas. You could definitely tell the difference.
The problem with this is that cooler running engines do tend to wear more....
