Cobra / Mach 1 brake upgrade from BuyFordRacing - unless you are building a TRUE race car (and not just a weekend warrior), you're pissing away money for overkill bling. Now go get that big bookshelf wing for the back and talk to us about all the downforce you gain (like you really need it...)
I would argue that a 4 pot caliper would be the most that anyone would need.
A 6 pot caliper, however, would most likely be overkill.