Not yet... That is my next step. However, I don't know what my car's threshold is. It has polished combustion chambers (piston tops, valves..) so there shouldn't be any hot spots, but it is all aluminum (with steel sleeves, of course). The engine is built from the factory to withstand 7,000rpm, and tests had them up to 12,000 without failure, so I imagine they can withstand some heat.
hmmm you'll have to do some research into that. I mean you'll probably not melt your exhaust manifold because something else would happen first like melting a piston. But the EGT can give you clues to how lean you can safely run, but who knows where the limit is until you reach it?