You gotta go bigger diameter to create a larger moment, all other things being equal.
Unless they are going to replace the master and/or rejigger the pedal ratios, then all other things essentially *are* equal and nothing will change.
You might get a better brake feel from a stiffer caliper, or even better braking in some scenarios (and worse in others) by changing pad compounds, but there is no magic bullet that will give you a bunch more braking force under a 17" wheel, or else Ford would have already done it.
If you want the perfomance that big brake kits offer, you need to actually get bigger brakes and the larger wheels it takes to fit them.
Unless they are going to replace the master and/or rejigger the pedal ratios, then all other things essentially *are* equal and nothing will change.
You might get a better brake feel from a stiffer caliper, or even better braking in some scenarios (and worse in others) by changing pad compounds, but there is no magic bullet that will give you a bunch more braking force under a 17" wheel, or else Ford would have already done it.
If you want the perfomance that big brake kits offer, you need to actually get bigger brakes and the larger wheels it takes to fit them.