Overhauling calipers are easy.... the problem is being able to find a shop that can reference non-OEM non-USDM components. Crack open that phonebook and call around.
is this information confirmed? From the looks of it, 350Z Brembos, Nissan Sentra SE-R Brembos all look the same size to the DC5 one.The 350z with Brembos supposedly use the same caliper so you can probably buy a rebuild kit from the Nissan dealer for that.