I have piston slap in my 00 Chevy Malibu LS with Amsoil 0W-30 oil. Car has 42k now and doesn't use a drop of oil.
From what I have heard piston slap is more of an annoyance than harmful.
It goes away after a minute or so.
At least that's my definition of piston slap. Please correct me if I'm wrong.