To add to what has already been said in response, the beauty of combining flats with an active preamp - especially the extreme versatility of the Sadowsky preamp - is that your tone is not limited in the same way that it might be on a passive bass such as a Precision (I totally dig flats on a passive P-bass, by the way.)
This right here. I have flats on a fender p as well. It is awesome. But flats on the sadowksy p/j are like having the warmest rounds of all time with no brittle high end. Unless you are seriously into slapping all the time, its tough to go wrong.