I dont believe u do need to shave anything if ur going for the ek 262mm rotor/caliper upgrade, but im sure someone else can shed more light on this

The reason why if going ITR caliper is that the offset of the bracket used on ITR is different to the ek by 3mm

Just to clarify it, ITR, EK9 both use the same caliper and brackets, were as Preludes and some other honda's all use the same calipers but different brackets.