Will a slightly lower temp thermostat and some water wetter or similar product not work for you?
During spirited driving with my zetec, a svt, and a v6 cougar, only the cougar had coolant boiling over. My zetec (180 thermostat and water wetter) would get hot but only because the high speed fan failed to kick it when it should. The svt had no problems. I'll find out next month if my svt does the same, but so far I have not seen it get above mid-ways on the stock coolant temp gauge (about 192 actual ECT).
