It is expensive. It will use your calipers on brackets that they will make for you so the cost is essentially the rotors+brackets+install. Like what Phone said, OE brakes work just fine, you won't be able to threshold-brake the car because the ABS kicks in early compared to other cars. I was using OE pads on these rotors till I went through 2 sets, and just recently used a set of Bendix (I honestly do not know what they are, they slap 'em on and I drive them and wait for feedback) and though they bite better, ABS kicks in a bit earlier than the OE pads. What's good about these rotors is that, even on OE pads and lines, brakes feel the same all throughout 7 laps (3.6km/lap) even when I turn in under braking and/or trail-brake. The size of the rotors I'd say not much help from the OE size but the cross-drilled holes and slats help keep the pads free from dust, dirt and cool down the brakes faster. This size Runstop rotors is a first for the Mazda2 here, I think they will have a few more sizes to come, hopefully I can get a chance to test them as well.
kcdirtbro54, about the setup, are you referring to the overall setup of the car? or just the brakes? The brakes are all OE except for the rotors and the caliper bracket. Rear are still drum brakes.