You would be wasting both your time and money with the G-03x. The internal clock of the K-01 is better than the G-03x. If you can't afford the Esoteric rubidium clock, be happy with the K-01 and make improvements elsewhere in your system.
Even with the rubidium clock, the degree of improvement is not great, and is totally dependent upon how revealing the rest of your overall system is. In some systems, you would definitely hear a difference; in others probably not.