I'd call Racetec. They'll give you options for minimal cost. Or, just buy the Mahles as they have clear advantages in a shelf piston. I don't think you can go wrong either way. Diamond is going to be quite a bit more expensive.
https://www.lsxceleration.com/search.php?search_query=Mahle+pistons§ion=product ofttimes has deals on Mahle pistons for the LS guys(I got a smokin' deal on two sets I bought there) I'd call them with the Mahle part umber and the best price you've found and see if they'll beat it. Great no BS shop.
