some details.. taken from Nissan Global Site..
1. Bore circularity machining & mirror finishing
2. Plastic intake manifold with integrated tumble control valve
3. Large capacity EGR system
4. Offset cylinders
5. Fine spray injectors 12points
6. Thinner water jacket wall
7. Long-discharge ignition coil & M12 spark plugs
8. Front intake/rear exhaust layout
9. Acoustically equal length manifold branches
10.Silent chain drive
11.Coolant pipes built in
12.High-adhesion FIP gasket and chamfer shape
13.Cracking-processed connecting rods
14.Continuous Valve Timing Control (C-VTC)
1.8 only in Malaysia 
15. etc etc..
Low-end torque for real-life conditions
Instead of going for full-throttle performance, we sought to satisfy everyday driving needs with ample low-end torque that extends linearly through the mid- to high-speed range.
Class-leading environmental performance
We minimized friction in the cylinders, pistons and other major moving parts, while refi ning the intake/exhaust systems and cooling performance to gain combustion effi ciency and superb environmental performance. We also reduced size and weight to class-leading low levels.
Not only quiet, but music to the ears
By maintaining quiet operation and minimizing discordant sonic components, we created a pleasant engine sound that adds to driving pleasure.