Brom, leaner mixtures burn hotter yes. But the heat is NOTHING LIKE what the engine is getting on boost - it's negligable so will still cool down significantly. I understand the thinking behind it, but when it comes down to it it's going to be a negligable difference. I'd rather run lean for a nice clean engine. Carbon deposits on piston and valves from a rich mixture causing hot spots are far more dangerous!
But yea, back on topic lol.