Engine temp, DX3 telemetry sensor
 

A friend of mine gets good temps 100C when racing around but if he slows down or comes to a stop the temp starts to climb, is this the norm or is his low end too lean?

Ive heard that after coming to a stop for 5-10 seconds then gunning it it should bog slightly before taking off, is this correct? His takes off instantly, is this another sign of a lean low end?