Thought I would add some info since I have done a lot of research into brakes for both the Taurus and my project (Merkur XR4ti).
Stock 10-12 Master cylinder is 1.062" (1 1/16")
I cannot confirm the 13+ Master Cylinder size, but I've found 1.25" which is a 12% increase in area. Napa listed the front portion as 1.5", but I cannot fathom that size, which doubles the area, so I'm going with the 1.25")
Piston area:
Front: 5.49" (2x47.5mm/1.87")
Rear: 2.25" (1x43mm/1.69")
The Mustang Brembo brakes use a 1.062" Master cylinder.
Piston area:
Front: 4.3" (40/44mm) a 28% decrease compared to stock
Rear: same 43mm piston as the Taurus
A big problem with the Brembos is the size (height mainly) of the pads. It will require the use of the Mustang 14" rotor, which is NOT hub centric and nobody makes a centering ring that will work, so more custom work. Or a custom 14" rotor, which are in the ~$250 a piece range. The caliper will not bolt right up. Wilwoods will work on the stock 13+ rotor, so a simple Caliper upgrade is viable.
Getting the same "feel" as the 13+ can be done by simply going with a smaller piston area caliper, which are available from Wilwood to within 1% of the stock area in proportion to the smaller master. That is based on my assumption that both the front and rear pistons are the same 1.25" on the 13+ Taurus.
