Pro-x (oem) is fine for the 200. OEM is not fine for the 220.
But then, wiseco may not be fine either if you happen to get one of their pistons in which the wrist pin clips don't seat. Be aware of that problem.
If it's a 200 and pro-x is your choice, be sure you get the proper alpha designation for your bike. The cylinder and head are stamped with a letter that should correspond to the piston. Pistons from kawi are generally 'B', but you can't specify that when you order one.
The correct piston can be had direct from pro-x....or a shop that sells pro-x.
The diff between alpha designations is .01mm, or roughly .0005" (1/2 of one thousandth). Actually .00039" No huge deal...but as long as you're doing it, might as well do it right.
Of course, the piston should match the bore it GOES in...regardless of whatever letter happens to be stamped on it.
Good luck!