You could probably use the hubs, only if they mount the rotor from the front instead of the rear, and the inner and outer bearings. The caliper will not fit the 993TT rotor. You need the 993TT caliper for this upgrade as well.
Before you buy the adapter hats, buy the 993TT rotors and test fit with the hub. You may be able to modify the caliper adapter (which you'll have to machine) so the caliper sits 5mm closer to the spindle.
The rotor hats space the rotor 5mm more out from the spindle to prevent the rotor from hitting the spindle, but you may be able to machine a spacer for the bearing sleeves that serves the same purpose.
I have the plans for my caliper adapters prepared, just getting ready to send to
www.vdubcustoms.com for machining. Hope to complete this swap in the next few weeks.
Sandeep