The run times with my 5000mah pack gens ace I can get anywhere from 8 to about 15 mins of runtime depending on how I have it geared and what settings I have on my rx8...

I have no experience with the tenshock motors, just what I've been told by other users about them being power hungry, if you shop around on rctech you can find the pro4's going for a good price. I wouldn't mind trying out the tenshock motors however since they are 550 4pole sensored motors, so it'd be nice to compare it to a 4pole 540 can motor...........