Always an excellent question to ask when flying high power. Nothing quite as frightening as a G+ rocket that is out of control! :y: Of course, G- rockets can be quite thrilling as well... :eyepop:
You're adding mass pretty far forward, and that is *usually* a good thing. You are offsetting the rockets CG from the thrust axis, which can result in some changes to a normally straight boost. Something like the starter BoosterVision camera should add so little mass as to be insignificant in a rocket the size of a Phobos. Unless you stick it way off the thrust axis on a boom, for instance.