A caliper is not only easier to change but it is also a hell of alot cheaper than doing a master. When I installed my stainless front brake lines the calipers were fine, no problems at all, put them back together, bled them then went for a test run. All of a sudden the LS caliper starts to seize ever so slightly WTF? Turns out the piston had a slight bit of dirt/rust on it and when I pushed in the piston to put on the new pads it went into the bore and will not come out smoothly, the rust/dirt scrape the smooth machined bore. So do your caliper before deciding on the worst possible case scenario off the hop.