there are a couple rotors that might work for a smaller package, also the standard boxster calipers are slightly smaller so would fit a smaller rotor better. AS for the bracket I think is doable I t would have to change a little so the caliper is not spaced out as far from the hub. going down to a 290mm rotor you would have to lose about .75" off the bracket. this only leaves about .5" of threads for the caliper bolts. prob enough but it would be a safer bet to switch to a stud that screws into the bracket and the use a nut to secure the caliper. pretty much the way stoptech does all their brackets.