The little blurb about SLX vs. SL was interesting. I have an SLX Serotta and it's the second stiffest steel frameset in my stable (being beat by my modern Colnago).

Of course there are other factors involved but the SLX in a 56cm seems to be stiffer. It wasn't confirmation bias, because at the time, I assumed that the SLX was a "thinner/lighter" tubeset than SL so the expectation was for a more lively frame.