The JRSC on an MTX car is pushing around 145+ HP, mine did 153.6 before adding a smaller pulley. But to answer your question, the JRSC and the ATX is not a good mix. We've done two of them and both of them performed rather poorly. One of guys even replaced his ATX with an aftermarket high performance built tranny and even it didn't perform as expected. Don't mean to burst your bubble, just sharing real life experiences.