I checked the owners manual, and it indicated two different sets of tire sizes. One for normal suspension and one for the sport suspension.

Normal:
F 205/55/16
R 225/50/16

Sport:
F 225/50/16
R 245/50/16

Being interested in handling, other than rim and tires, are there any other differences between the two? What would it take to change from a normal setup to the sport setup?

Change the rims first, i've got 928GTS rims on with the 245/45ZR/15 and they stick like glue.

Sport suspensions used different shocks (koni), larger sway bars, and possibly different spring/torsion bar rates.

need more specifics? Then I'll need the year of your car.

Mine is a 1991 944-S2, and I'm hoping to get it into shape for the local Porsche Club's Drivers Education events on the local road track.

Granted, it may be awhile until I can get to the suspension upgrades, but still, I just recently noticed the differences while I was reading the cars woners manual.