I thought some of you might be interested in reading/discussing this thread about 300zx's i saw on reddit today:

My opinion is that it is not as good a base for modding as a skyline or supra which is one of the main interests in JDM cars. The skyline has an iron block and despite having less HP to begin with, can handle more boost and mods on the stock block making it a good platform. The supra has reasonably the same performance as a 300zx but the 2jz is more compact (idk) probably better for modifying as well (also more engine room in supra)

 

Looks obviously plays a part with the 300zx not having such an aggressive design as it is a tourer supposedly.

 

Overall though i think advertising and most definitely Fast and Furious largely influenced the JDM cars, and as both the skyline and the supra (both driven by Brian/Pual walker) were both center stage cars in the movie, gained much more interest than the 300zx which wasnt in any of the movies.