Can I put an Fighting Bro 3.0 V2 in my gen8?

I want to Upgrade my gen8 with a better gearbox and I heard that the FB 3.0 is good so I was wondering if it would fit and if not what would be the best gearbox to put in a gen8

No it won’t fit, the FB is a v2 style gearbox.
You will need to use a gen8 style gearbox and there are quite a few.
Apparently the Lucky gen8’s are good ?