i ran the rx8 with the 4pole redline 540sct 3300kv motor in mine,i ran it for over 20mins,the heat read out never went over 3,it goes up to 10,someone i know runs a 550 motor 5.5 on a normal 1/10 spec speedo and struggled to do 6 mins before it shut down,
you dont need the rx8 but its top notch and you can be asured it wont let you down
the combo was super smooth but still quick