I have the Mountune rad and stock thermostat, and did do I think maybe 2 bottles of water wetter (cant remember for sure). When temps are in the 40's and 50's I'm at 192-197 highway cruising. But the temp essentially doesn't change idling nor in hotter temps. Its been near 100 and sitting for 15 mins idling with AC on its basically the same. But, even the slightest grade increase and I can watch the temp go up. It's never high enough it seems scary, but I dunno.