I think the OP wants to know if they should replace entire studs or
just the bottom part. I'd say that depends upon how easy it is to do
either one and the etent of the damage and locatin of the stud. We
really can't tell without pictures, and even if we had them, it might
not be obvious since we don't know how much damage is inside the wood
that we can't see (since it's often more damaged in the interior. If i
had to say anything it would be to condier replacing with metal ones
if you do a whole stud since that way if you ever get water in the
basement again you won't have to worry about rot. In my basement I put
three coats of oil based polyeurethane on any new pieces I put in where
I replaced rotted wood.