Let me address SR; If you look at Special Relativity, space-time reference is connected to velocity. Velocity has time built into its units; v=d/t. SR seems more cut and dry, relative to time, impacting space-time. However, changes in space-time are still mass dependent, since pure velocity; d/t, without mass/substance, will not allow a tangible or experimental change within space-time. In other words, imagine a massless object moving at velocity V. If we use math, a plot on paper, or just the imagination, there will be no tangible change in space-time, simply by going through the motions of a mental or computer exercise. There will be no experimentally verified change in space-time, using a velocity abstraction, without mass. There may be changes on paper, for an academic exercise, but not in physical reality. Motion without substance/mass; abstract or imaginary motion, may involve time, but this type of time by itself, cannot alter space-time in any tangible or experimental way.