Tiger motor, Antigravity series vs Navigator Series ?

[maxwelltub]

Is the antigravity series just a marking thing? What the difference here?

http://www.rctigermotor.com/html/products/ANTIGRAVITY/Antigravity_Motors/

 

[Hexacrafter]

I would have to look into this deeper to confirm all of the differences, but thought that most of this line have much lighter case.... Less weight than a MN.... But some even have what appears to be the same case, so I am not sure.