I run 5s in my xt8 with a neu 1512 3d no problem. I run the updated 3.17 program, lvc set to custom 15v, and a fan. Using a true rc 5000 pack geared in the 30s I get about 25 minutes of run time. The motor runs about 150 degrees, battery 120, speedo 120. Granted, this is in the desert. I fully charge all of my packs to 4.2v a cell, so far no problems with the speedo.

My neighbor over here uses the same setup in the same car except he uses a 9xl, it runs a little warm and has thermaled before. He has a 5s 8000 true rc pack, its huge, and its geared in the 40s. It truely states how tough a mm is.

In my revo I have run the mm with a neu 1515 2.5d with a 5s true rc 5000 pack without any problems. I did not keep it that way because the run times were only about 20 minutes at the most.

Cogging the with mm/neu combo is not much of a problem in the revo since it is forward only but the xt8 is noticable. Its really not a problem unless its a rolling backward start, then it will take a second to react.