TR6 pistons, what type/size

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My engine is being rebuilt using a hotter cam and more compression,
everything else is balanced, but stock.

What pistons should I use?
What do they do to make the 2.7 L engine?  60 thousands overbore?

Pro's and con's of piston choice vs. compression, etc.

I seem to recall a Mazda Forged 4 cylinder piston being a perfect
replacement for 1/4 the price of OEM pistions?

Thanks,
Roger