N1 engines use roller bearing metal turbochargers instead of the standard ceramic turbochargers. Other differences are reinforced engine block, reinforced piston and conrods, different piston rings, different oil pump, different water pump, different exhaust manifold and different intercooler. (the list goes on!) I read somewhere that the engine output was around 330kW's.
The N1 engines are hand made at the Nissan's racing engine division (NISSAN KOHKI).
Hope that help