Ah okay I think I have found my answer, I've only been searching for an eternity!!
The 'G' is effectively 'OEM' for that bike. So Honda may have worked with Bridgestone I presume to 'tweak' the tyre in order to increase performance or something for the NC700X in particular, I found this applied to alot of other bikes.
So the extra you are paying for is most probably the cost of their R&D! or as someone else put it, 'G' is for gullible if you're willing to pay the extra for essentially nothing. ;D
If anyone can confirm, I'd be most grateful
