The MS-X chassis will be different if not just for the rear bulkheads. The MS-X bulkheads are longer and probably different screw locations. Since the MS suspension pin is 46mm compared to 48mm for the regualr 415, and you have more than 2mm in spacers, you should be able to mount a regular suspension. The difference might be where the droop screw goes through the A-arm and if it will still hit on the chassis.