Hi@gte357s,
Good question that I should have addressed in prior comments. I purchased my CSLS MK II new in 2009 and it came with the Shuguang 101d. This is a good sounding tube at very reasonable cost and is also reliable.
I switched to the Psvane W.E. Replica 101D in 2014. This is a "great" sounding tube.you can hear improvement across the sonic board/spectrum compared to the standard Shuguang 101D. This premium level Psvane is more expensive but IMHO worth the additional cost.
Good versus great , even more air, openness and inner detail and nuance. The Psvane W.E Replica has a fuller more meat on the bone presentation (Relatively speaking) yet remains remarkably transparent and more dynamic. I’ve had them so long I consider them my "standard 101D
Charles