Grounds do make a difference I saw a steady .2 voltage increase from adding a ground from the alternator to the engine block then another to the frame and another to the factory battery location like you have I'm waiting for more money to finish the build I will be adding another two runs to the SCIB bank in the back I finally got the Tyrant bumping on the Cab-45 I haven't went above half gain so far trying to break it in but it is a monster