Thanks for your advices !
Yes I've also been looking at the Fury bass, that seems to be a really nice one, certainly lighter !
BTW, There is a Fretless Fury with just 1 super Ferrite PU on Ebay now ...
So I come to the question : What is the advantage of the 2 Humbuckers ?
Answer : you can get a lot more different sounds than with the other PU config, right ?