dedicated preamp.

You should get better SQ. It will all depend on getting a preamp that's better than the one you're using now. I would definitely recommend that you try a new preamp first, if you can. The preamp section on your passion 100 should be pretty good.

I don't think it would make any difference since you are staying with a YBA preamp ! I think if you call YBA they will tell you the same !

You really think they would tell him that there's no improvement in sound quality as he moves up the YBA line? Why build them if that's the case?