Yes. Cut the ground. I have a friend that races with me, and he is an Automotive electrical mechanic (starters/Alternators/etc..) by trade. I had mine done + side, and he scolded me for it. the issue is if you break positive it can be shorted by anything on the car. If you break ground, and it is shorted, it is still ground. (ground short to ground vs positive shorted to ground). I am simplifying the response, and I might have it slightly wrong, but I believe that was the gist of it.