I'm not familiar with roar rules but if the battery has to be a certain dimension than okay fine. I'm personally excited hpi is continuing the pro line. My first rc was the original hpi pro and that thing could withstand hits on curbs at full 9 turn speed unscathed. This could possibly get losi back into the game and maybe even traxxas. I would love to see permanent tc tracks pop up around the Orlando area. Why couldn't hpi at least give us a teaser sketch or something.