Wow... I feel for you ED. Due to the nature of RC and nitro engines , you get a guy with failed motors or that wont tune and they automatically blame you.
Well. Its the nature of the best. I also believe when hes modding motors and pretty much anyone else unless instructed to go beyond normal means you wont find a motor dying due to a modifier unless they are just seriously retarded.
Tearing/fanging spots on a motor isnt going to cause it to prematurely die....but I really have no idea what Ed is doing.
Anyhow , good luck and allthough ive heard bad too , its easily overcome if you do come up with a clear and defined policy that competitive with others who have good standing names...simple as that.
But beyond that who offers warranty on nitro motors anyhow? Not many and if they do its courtesy.