I don't know any more, I did all the research
over 2 years ago when I first did the turbo swap.
$400 bucks was out of the price range for me so
I just did it witht he stock pistons.
One alternative would be to mill the top of the
factory pistons to reduce the CR, but this also could
cause a weaker piston, so I would mill carefully
I plan to do another turbo for myself again, with
longer stroke and bigger bore, so I will go the custom
piston route then, also piston oil squirters to keep them
cooler too, fun stuff this turbo stuff is
