Don't know about that. We still have a fairly healthy Slash Spec Class at our track and the difference between Spec Slash and Open SCT is only 1 -2 second on average. This is on a technical indoor dark clay track that is kept watered. Only changes allowed are radios, setup, shock caps, bodies, and any pinion that will fit the three stock gears without modifying the trans for it to fit. We have guys that run Slashes in the open class and they hold their own against SC-10s, Blitz's, & XXX-SCT's (no one is currently running the Ultima SC right now). Some have proline kits and some dont.