I call bullshit, no way the modified the engines. Those are gt3 cup cars (the "lowest" racing version of the 911) with different supension, tires and hydralic handbrake. Maybe they also needed to fit a reserve tire in the front. But no way they changed the engine for customer rallying in the r-gt category, where it is already 500hp compared to the 300-400 hp of, say, a alpine r-gt