I currently run this configuration at the moment,
and my understanding so far that it is higher compression to run the 100 KW bottom end due to the shape of the piston.
ill take some photos taday but there is distinct differences between the pistons, and there may even be a third piston which is a really high compression piston similar to that of TODA racing pistons which have a compression of 11:1 (which i just fractured one of in my engine )
the centre of these pistons raises a little more .The ACL replacement 100KW does not raise up that far, and the 86KW pistons do not raise up at all and in fact are recessed completely. I would be interested in a pick of someone elses 100KW factory pistons to see if there is any difference.
But basically it is a straight bottom end swap and everything lines up.