"The 1.8 L (1769 cc) QG18DE was designed for Nissan by Aichi Machine Industry, Japan. It is manufactured both in Japan and the Mexican city of Aguascalientes. Bore is 80 mm (3.1 in) and stroke is 88 mm (3.5 in). The engine is tuned to achieve most of its torque at low revs at the expense of raw power at high revs, making the engine very responsive in day-to-day driving. It has a cast-iron engine block, aluminum DOHC cylinder head, uses MPI fuel injection, forged-steel connecting rods, two single-piece cast camshafts and a cast-aluminum intake manifold. It also features N-VCT (Nissan's Valve Timing Control technology). This engine received the RJC Technology of The Year Award of 2001.[2]"
Above is something found on wikipedia
You can read entire Nissan QG Engine article at http://en.wikipedia.org/wiki/Nissan_QG_engine
As far as I know most of the Engine parts would be same as 1.5 QG15DE.
And 1.5L auto is not that under powered & if you really really concern about the power, ya you may go to 1.8.
Best thing is you call to A*W and ask them all questions/doubts you have in your mind.
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