I have a 380x motor that will be here friday, to put on my hbfp.
I talked (e-mailed) to the tech dept at xtreme about wether or not it would fry the 4in1 like I had heard. They said that the stock blades have too much drag and load up the motor too much and that is why some people have fried the 4in1. They also told me that the set up that they recomend is 380x motor with either xtreme 8degree pitch wooden or xtreme plastic blades and everything will be fine.
I asked if I needed to install a fuse between the 4in1 and the motor and thay said if I use the combination above, it wont be neccesary but if I absolutely wanted to they recomend using a 10 amp fuse.
Here is the site that I went to and asked the questions.
I did put a set of 10 degre pitch wooden blades on it with the stock motor and it's amazing to me how much better it flys.
Hope this helps!
J.