My personal data shows on the stock thermostat, I'd average high 190*F temps on the highway and saw irritatingly high 220's at stops.
Now, I'm supercharged, and see mid-180's on the highway and very rarely see over 205 when stopped. The only time I've seen over 210 was when I was idling while not wanting to go to work when it was 95+ outside.
Highly recommend this if you plan on pushing your car at all or live anywhere where you see above 80* temps regularly.
