OK newbie on Milwaukee, I have bought a 2704 M18 Fuel Hammer Drill and a 2656 M18 Brushless. I am looking to add a impact wrench. My head is spinning on this thread with High torque vs Mid torque, Compact vs non compact, heavier vs lighter, M18 vs M12 and fuel vs non fuel, 3/8 vs 1/2. I am a...