There's no loss in power. You're just tilting the scales in the direction of low end torque instead if high end speed. I'd say that you were probably maxing out because of the rev limiter. Going WOT with portals is no different than WOT without when it comes to rpms. The motor is still turning the same rpms. Its geared down out at the wheels now for added low end torque for bigger tires. Getting rid of the rev limiter will help if you're worried about top end speed.