I certainly would not have the fans on all the time, that is not a good idea, they should only be on when needed, i.e. in long slow moving traffic ques, if anything I would look at changing the fan switch to the "Uprated" one.

The Sierra/Granada 90 amp Bosch unit are the same, and no only high spec Sierra models had this unit although the pulleys may be different on some, not sure if all Granada's would have the same unit either.

Martin