All depends on whether the crankcases have to be split to be machined out. On this occaision, I think that this would be the case.
I had the 853 kit fitted by Neil at Sigma. The pistons weighed the same as the originals so no need to balance the crank of machine out the cases.
If the kit was cheap enough then I would go for it. Thing is, once you have split the cases and balanced the crank. I would have thought that it would not be that far off of getting a 955 set of pistons in there.
Unless there is more work needed.

DC.
