Thanks for the pointers.
Follow up question then: Dirty Drives or Clean for speed boost and low heat and/or energy usage?
short answer: for an explorer, take clean drive.
long answer: dirty drive has less of power increase, and therefor your resting heat will be lower with dirty drives, while it significantly produces more heat if you boost and aceelerate a lot, and above high-G surfaces. you'd be probably better off with d-class dirty drive thrusters than clean drive a-class thrusters, because d-class thruster need less power and build up less heat when under heavy usage.
i have dirty drive tuned a-class thruster on my DBE, which now can't highwake while boosting from a black holes body exclusion zone, while my explonda with a-class clean drive tuned thrusters can.
there aren't many reasons to go for clean drive, exploring surfaces or exploring at all is one of the few.