Pass Labs X-250.5 vs X-250.8 Stereo Amplifier

Has anyone out there ever listened to both the Pass Labs X-250.5 and X-250.8 stereo amplifiers? If yes, how do they differ in sound and sonic character? What improvements does the X-250.8 have over the x-250.5? Which among the two of them is more full bodied and warmer sounding? Is there anything that one does better than the other? If yes, what are they? The reason on why I ask is because at the moment, I have the Pass Labs x-250.5 and I was just wondering if it is worth upgrading to the X-250.8?
Thanks in advance.