[KingLT1]

There isn't really anything "critical" per say. If MAT's get above a certain temp the ECU is only going to allow so much timing advance to protect the engine. The hotter the MAT the less timing the engine will be fed in order to keep KR at bay. Engines running E can run higher temps without pulling timing vs pump gas. This is all controlled by the IAT vs Spark table. Mine doesn't pull any timing until MAT reaches 154 degrees. I don't believe I have seen it get that high yet but it doesn't reach 100 here...usually 88-92 degrees in the summer. Even after a hard pull at those ambient temps my MAT are hovering around 128-135. I am sitting between your 600 & 800 goal posts for power with high compression running E50.