Look into the ca16de piston. I've got a set here and at 78mm they look like a good cross fit for the a14/15. They have a slight dome that would need to be milled for whatever c/r was needed.

Strong piston too with drilled oil returns instead of slotted. Also have full floating pins. Obviously a performance piston even though it's not forged. Clearance will be more than a slotted piston but less than a forged so the durability would be good too.

I returned a new set of ca16 from ebay because they were slotted. So probably only OEM or good drilled aftermarket if they're out there.