Well TBH these stories have admittedly made me weary of getting the MGM for my conversion. I don't mind buying a $90 motor to replace a burnt one in a hurry, but a $300 ESC is another story. I would hate to have to buy a second one just to keep me running while my main one were repaired.

I'm seriously considering giving a Kontronik Jazz 55-10-32 a try. For one thing, it will allow me to run 10S which is just what I want. And another thing is Kontronik have a good rep for their ESCs (even though not for car use), and they even have an official Kontronik forum on RCGroups which is great. At worst if it doesn't run nicely in a car it should be easy to sell because it's a very popular and highly regarded heli ESC. (I have two smaller Jazzes in my helis)