I got my new S20 Evos on. 55 rear and about 400 miles on them. This is my first shot at a 55. I can't tell any difference between my M7RRs and prior Q3s (50s) in fact I'd say overall steering quickness is slower. M7RRs and Q3s were quicker to turn even with 50s. I think it may be more the tire's contact profile (more round), with the M7 and Q3s having more of that "egg" shape than round shape.
Next set of tires I might go back to M7RRs with a 55, since I think as a set of tires they are more on the sport side and less on the ST side.
Overall I like them ok, not disappointed to have them on the bike but not a new favorite. Most important thing they seem to have good side grip and warm up quickly.