Hi Harold,
We used Wossner pistons on a friends bike which lasted one weekend at the track.After which he had to buy another set of pistons and a Nikasil so not so cheap... Be very careful with regards to piston to wall clearances, especially after a re-plate from NSC.
Two other things to mention :
1. The wossner piston is shorter so you will have to cut your barrels to accommodate or face loosing the compression.
2. The wossner ring pin runs over the intake port instead of over the bride between the two ports like the OEM piston so potential ring catching there. ( This is basically what happened because of the PTWC being too small. )
Cheers
Mario
P.s I do have OEM pistons in stock so email me if you need.