I could be wrong, but I believe the S-Maxx is a 2wd, while the T-Maxx is obviously a 4X4.
Thats it in a nutshell. The S Maxx has a two speed forward only transmission while the
T Maxx 2.5 has a two speed transmission with reverse.
The S Maxx has a body, tires and wheels unique to the S Maxx, a 3.3 engine was
available in later model years, and the S Maxx was only available through Hobbytown USA.