Dick, Freddie (my ex-partner,) and I ordered our pistons from Wiseco along with a set of K-1 rods and the pistons were delivered with"european" rings, which we then had to file the end gaps on. Those rings are thinner and lighter than OEM stuff. Supposedly, better...
Just FYI...
The k-1 rods might be lighter than OEM 198 rods, but I am only guessing.. The K-1 rods that fit the cast crank ARE considerably lighter than the ones for the forged crank; probably because the bearing is narrower, probably making the whole bottom end of the rod narrower, as well. More esoteric information, requiring yet, more decisions... LOL!