Cool. I was talking about this kinda mod.
What mines has done here is taken hr15 short block
Attached hr16de piston and connecting rods to the hr15de crankshaft
The stroke and bore remain the same, the hr16 has shorter rod. But taller piston height. So they share the same profile which different fulcrum.
This changes the characteristics of the engine.
I believe they have a stock hr16 head and are just upselling the factory finish on the hr16head.
View my fuel log 2015 Micra S manual: 7.7 L/100 km ... 36.8 mpg (Imp) ... 13.0 km/L ... 30.6 mpg (US) ...