Is my chain getting yanked?

[Field Scout]

My xm is giving me trouble , it was dealer installed and the aftermarket guy said the problem is with the battery terminal connetors since they are not oe,(oe ones removed when winch was added) says the connectors have a high resistance open causing me to loose 4 milliamps thus screwing up my xm. also said this was important because the system was preciesly designed and could not allow for the slightest variance. maybe I should just scrap the factory setup and go aftermarket w/nav? If i do a stereo up grade any suggestions?