Is grinding a few millimeters of metal off of a pneumatic cylinder considered a modification? It is not improving performance in any way. I have read <R14> [No modifications to electronic or pneumatic components are allowed.Motors (including the internal PTC or V5 Smart Motor firmware), microcontrollers (including V5 Robot Brain firmware), cables, sensors, controllers, battery packs, reservoirs, solenoids, pneumatic cylinders, and any other electrical or pneumatics component of the VEX platform may NOT be altered from their original state in ANY way].
Is original state meant to include the base, which is just for attaching the pneumatic cylinder? I wouldn't see how grinding it provides an advantage. The new vex reservoirs take up more space than the previous version, so using the previous version provides advantages in terms of physical volume occupied.