Well it is much more than just RPMs which is why some say we will never have a true equivalency between brushed and BL. The 25.5 may be the same in RPMs or very near to a silver can but it has much more torque so can utilize a higher gear ratio and be faster. Even if you limit the gear ratios the BL will have a slight acceleration advantage. That said we tested and ran the Hobbywing system with the black can Tamiya motors in our mini class and were pretty happy with the results.