Personally, with the consistently low quality I've seen in all brands and styles of thermostats, I'd recommend testing any thermostat before you install it. Suspend it in a pot of water on the stove to make sure that it opens at the correct temperature and that it opens and closes completely. It's far easier to detect and return a defective thermostat when you haven't installed it on the vehicle.

95 Montero SR
3.8 MIVEC, Advance headers, 2 1/2" exhaust, Magnaflow muffler, OME shocks & rear springs, 2" body lift, 3" tank lift, 4.90s, TRE front locker, factory rear locker, Roger Brown Rock Sliderz, 315/75r16 (35") tires, Sport big brakes