Somebody on this forum recommended Niks Industries for Wossner Kits.
I checked them out and they had the least expensive retail price (by far) of any place I found. Then, as luck would have it, they were having a flash sale of 40% off on-line sales that weekend. The whole kit ended up being $ 80 some bucks including fast, free shipping.
That was for a '01 XC 200 w/ B piston.
Next time I did it, I wanted to use a C piston to allow for a worn cyl. Found a Wossner C kit on ebay for around 120 bucks inc shipping.
The Wossner deals are out there, if you shop around. I'd check Niks Ind first, though.
Now I have a new oem cyl kit waiting for when the C piston kit gets too tired.
It has the Vertex piston which I'm sure will be fine. I also used a ProX kit in a 400 DRZ I had. It's still going strong too.
RB