Alot of what you're experiencing is related to the type of plug you're using and the tune of the engine at the given moment, for example a hpi n5 plug is a cool running plug, it generally gives a cooler running temp but, requires a slightly richer tune and takes a little longer to warm the engine up from cold. Whereas an n3 is a medium/hot plug. So more or less the opposite. Just be sure that you're using the recommended plug for your block, if the engine is running well without running too lean and your temps are high, just drop to a slightly cooler plug.