From memory yes the MC28 motor will go straight in but you will have to identify the neutral wire from the GPS (gear position sensor) for the MC18 wiring loom and you will need the flywheel and pickups from the MC18 which should fit without any issue. I wouldn't be too worried about compression or power....should be very close to an MC18. From what I have read most of the problems with liberating the power from an MC28 come from the electronics and pipes.....