From what Ican tell, more adjustments. From one model TT01 to another, they're basically the same.

To see the differences, go to Tower Hobbies. They list the pertinent info on all they sell. If you go to the 1/10th on-road car kit section, you'l find all that info. Click on "spare and option parts" to see what's available for the TT01, too.
You need not buy from them, and I'm not telling you to, just to check out the info, so you can make an informed decision.