Does anyone know how B-Spec mode actually works?

[Jujubean]

I am pretty sure you do get xp from online. My Bobs have gained a ton of levels from remote races.

 

[Jamie078]

I'd like to know the advantage of having more than one B-spec driver. Are they really all that different, or do they behave the same (given your race orders)? I've got my Bob at level 14 now, and am allowed to have "up to 3" B-spec drivers. What's the point of having more than one?

You will need more than one b-spec driver for the Endurance races, among other things.