Hi phisher, been awhile since i ran that car. In the lower motor classes (21.5 brushless) i would use a one-way - help keep the rolling corner speed up. For faster motors i would use ball diff. Some guys i know use a spool, however i find they the inside wheel can break traction (spin) and then grip up suddenly and project the car in wrong direction. That was just me, so i find ball diff more consistant. Good luck.
I saw your post in the TB Evo IV thread about carpet set up. What type of front end did you run, spool, one or ball differential and what was the best set up you had for a short track. Any help would be great. Thanks.