[eschaider]

Greg,

The chances are better than good that the GM calibration engineers chose 105˚C for emissions purposes in the States. Your car is what I call an attitude adjustment vehicle and, as such, does not need to meet Federal emissions targets.

I do recognize that you guys have some sort of regulatory official that you must make happy before you can drive these things on the street among ordinary people. That said, you will probably find that an 82˚C T-Stat, what State-side we call a 180˚F T-Stat, will fix your excessive heat problem with the least amount of effort (and expense) on your part.