I have Sorpasso and Sorpasso 2 and have some top of the range Sportful tights from a few years ago - I forget the name. I also got some Fiandre shorts this autumn and found the same - a L in those vs the XL of my Castelli bibs.
Fiandre jersey and jacket were the same - sized down from my Castelli Alpha, although will confess that this gives a very snug fit with no room for any Xmas over eating!