What is the best piston for a D16Y8 stock all motor*?

 

This is an extremely vague question done in such a way as to be an opinion poll, not a technical discussion.

You have not provided any information on your goals to narrow down the opinions to become more technically focused.

When you have specific goals in mind for your NA motor, please do try again. Also you might find more knowledgeable responses (once you have clear goals) in the NA forum as that is dedicated to all motor builds/information.

I do know, a vague opinion poll question like this one won't fly in there either. You need specific goals so there is specific direction to dictate the parts required.