The RR6/7 engine is a straight fit however the ECU is mounted differently. RR6/7 ecu mounts on top of the airbox. The RR4/5 mounts on a bracket just behind the mid fairing. You can use an RR5 ECU however you will loose out 350 rpm if you use an RR5 ECU.Everything else is the same pretty much. The RR6/7 clutch is better.