setting position by x and y coordinates with system expression seems a bit pricey to me. why not use just some movement behaviours to do it? (custom or bullet), i think they're more optimized for performance then setting x and y every z miliseconds.
Heya, I do use pin if I want object to follow. Now, I really should have be more precised, because I am mostly turning physics on and off as well as set opacity, both depending on the distance from the player, every x ms, however I am not sure if that's necessary ( although my levels have floors, so I'm checking z position of the player based on other events, from which I turn on or of tiles physics).