gsx limited 951 failure

[brintros]

hello all,

I'm Nico from Belgium, i have bought a seadoo gsx limited that don't start ! I have started the jet and he worked fine just not go very high in rpm.
but after that i clean a lot and look at the piston how they are, and after that i see the scratches by inside the exhaust wow i need to open it.
now i need to rebuild but please say me what i need to do now ?
the other piston is in pretty good condition and don't have scratches, i think the failed piston was mounted in the wrong side because the ring's gaps was in the same side as the exhaust port

new head or it can be milled ?
2 new sleeves and pistons or we can mill the sleeves to a bigger hole , and put bigger pistons?

thanks for the help i'm new in jet ski's world.
but i have a good experience in other mechanical sports and rebuilds.