it all boils down to one thing, do you want a engine guard and body graphics or not. If you want then you can go for FZS Fi V3, if not FZ Fi V3.

But if you notice closely you will see that the body graphics would be present in FZS Fi V3 which is not there in FZ Fi V3. Also a big difference is that there is engine guard present in FZS Fi V3 ...