I have these two front wings and stabilizers. I have two complete sets because I like to have a spare and swap out for chip repair (often rocky locations). I originally got the two wings and just the 330 stab.
Moving from the old style Silente and still a relative noob, I figured I would start with the 550 wing as it has a lower aspect ratio and figured more forgiving. I have now tried the various combinations:
550 and 330 - My initial impressions were that it was way smoother and less prone to cavitation than the Silente was...was very pleased. Over time I found that at higher speed you could not relax at all from a pitch perspective....you had to increasingly front weight to avoid breach. Breaches were not pretty.
558 and 330 - These are meant to be! I found this a much more balanced combo front a pitch perspective at all speeds. I also don't feel much difference between the two front wings. Maybe a little more top end for the 558 and a little more lower end for the 550.
550 and 325 - I believe these are meant to be together and it solved the pitch sensitivity at speed BUT...I found the yaw very twitchy without the winglets on the stab. I did not really enjoy this combination at higher speeds. I think it would be better for playing in swell etc but not my cup of tea.
558 and 325 - have not tried it yet but I would expect it to require the opposite as far as pitch....more bias to needing rear weight as you go faster plus the yaw twitch.
I will probably sell off the 550 and 325 in favor of a high AR speed set. or the 548 (anyone have comment on this one?)