No stat is a bad idea. The temp issues aren't so bad if the weather is v hot, or it's on track etc. That's not the problem though. When race cars run without a stat, they fit a restrictor instead. The reason is, the stat causes back pressure in the cylinder head, and this is essential to cool the combustion chambers properly. Without a restriction, air bubbles form as the water boils, and heat transfer is greatly reduced. The water in the stat housing maybe nice and cool, but your poor cylinder head is cooking...