A guy at a Honda 2S told me that the only physical difference between the 2 models (1.3 aspire and 1.5 aspire) is the different crankshaft in the 1.5 engine (the radius of the crankshaft is bigger which displaces the pistons more, resulting in bigger swept volume).
Rest of the parts go by same part nos. And logically speaking this might be true as this does give the company an advantage in manufacturing / assembling.
