I just bought a 61" Tiger Cat SS with the 27hp Kohler. I inquired about the Wildcat and was told by my dealer that it is being phased out because it is so close to the Tiger Cat. The differences between the Wildcat and the Tiger Cat are:
1. Different engine options including LC on the Wildcat with the air cooled 27hp Kohler being the top offering on the 61"
2. Suspension Seat (SS) package available on the Tiger Cat instead of the soft ride seat
3. Adjustable levers on the Wildcat
4. External hydraulic oil cooler on the Wildcat
5. Flat free (Semi-pneumatic) front caster tires on the Wildcat
The frames, drive system, and cutting decks are the same.
Here is a link Scag's comparison page. http://www.scag.com/zeroturncomparison.html