There are not many stories of new stock tubes sounding better than their nos counterparts. Yes, it does happen, but it is more the exception than the rule.
The same can be said, in my experience, for many stock parts in general. Unless you're talking about the upper echelon stuff (MSB Select Dac, TotalDac 12, Aries Ceral Kassandra, etc...). And even then, you can make them sound better with better/different parts.
Most of the time, things are built to a price. Better parts usually mean better sound. Not always, but often enough to almost say always.
The same can be said, in my experience, for many stock parts in general. Unless you're talking about the upper echelon stuff (MSB Select Dac, TotalDac 12, Aries Ceral Kassandra, etc...). And even then, you can make them sound better with better/different parts.
Most of the time, things are built to a price. Better parts usually mean better sound. Not always, but often enough to almost say always.