Not sure if they have a complete system for Flex. I do have their pads with Power Slot rotors on front. Using my smaller lighter wheels/tires the stopping is very good if not great. However, my front rims look like they are the charcoal ones. LOTS of brake dust. But I don't mind... they have saved me from a couple accidents!
My rears are power slot rotors without the slots from TireRack... Ended up with Akebono (?) rear pads.