The 996 monoblock will fit in the same manner that little red, S4, or Big Red will. ie they require an adaptor to change from the stock 911 transverse mount to radial mount.
Here is a pic from my website showing a Big Red and a 996tt monoblock. The 996tt is physically smaller, but they do have comparable pad area. The regular 996 monoblock is even smaller.
Do you have 304x32mm 930 front rotors, if so the 996 caliper with the approprite adaptors will work fine. If you still have the stock Carrera rear calipers there will be a very slight front bias.