I've talked to lots of Skywagon guys over the years and have never run into one who had the Crosswinds cuff on a Cessna. Charly Center would be the guy to ask. http://www.crosswindsstol.com/products.html
An old 2001 Northern Pilot magazine I have has an article about a Crosswinds STOL-equipped PA12, and also mentions that the cuff kit was developed by Cal Center (Charlie's dad) & was / is available for the Cessna 170B/180/185. Pretty standard kit: cuff, fence, and wingtip. Unless the wingtips are real miracle workers (and the Crosswinds tips I've seen were pretty different looking), I'd guess that it probably modifies performance about like a Horton OWL MidAmerica or whichever other cuff matches it's profile.
My hangar neighbor just put his C180 up for sale. When reading the specs for it, I saw that it has a Cal Center STOL kit. Took a peek through the crack in the doors, and it looks like a moderate leading edge cuff (about like a Horton), with the usual stall fence on top ahead of where the aileron & flap meet. There appears to be a small stall fence terminating both the onboard & outboard ends of the cuff, so that it can use a normally configured wingtip and wingroot fairing.
I have one on my 73' J model. Cal installed it in AK when the plane was new. It's a little more added lift than a Horton and has fence at the end of the flaps. Also, a small forward fence at the wingtip. I've flown under it for 15 years an it is excellent. The plane is extremely stable in slow flight which is handy when flying on the back side of the power curve. I've flown and trained pilots with every STOL mod in the 180 & 185. Some are good and some should be left in the box. The Crosswind is at least among the best, if not the best.
Thank you for the info. I have seen a couple now that had that kit but in doing my DD they were either overpriced or had other issues I did not want to get involved in.
It is nice to here a good report on how well it actually works.