One thing I've notice over the years is that China-made pistons don't always match the Nissan part numbers
Nippon is the name of a country. NPR makes rings & sleeves but apparently not pistons. Can't find any company "Nippon" that makes piston. So the pistons presumably are made elsewhere
With A-series pistons the main consideration is to match the piston to the combustion chamber. Compression ratio is less important. The type affects the flow performance
the photo doesn't seem to match other G34 pistons
G34 is an offset-dish piston, used with H89 heads and other newer types including CAL emissions engines
H98/H92 is the same offset-dish type but different depths (H98 used in CAL engines, H92 used in JPN engines) .the depth affects the compression ratio but the offset interacts with the head and so determines the flow
All moot if you are not using an A15 cylinder head. The GX head is higher flow than any A15 head and was designed for a flat-top piston (10:1 with an A12 with the special thin head gasket)
Remember that 11:1 compression is good for pump gas, but anything higher might require special fuel
Custom pistons are $400/set to $1200/set so are not cheap