Importance of input tubes to sound quality?

I've been running  good pair of Mullards in the input section of my LSA Statement integrated for almost two years now and was contemplating rolling them for a really good pair of 6922's. The Mullards replaced the stock tubes and made a slight difference in the openness of the stage, though that may have been confirmation bias.

Before I drop several hundred dollars on a pair of tubes, do different levels of input tubes really make a difference in sound? Can they do so on a physical level (as in, is it physically possible for them to do so)?

Ditto for the stock 12AX7's in my Jolida phono stage.