Better to change Speakers first or new Preamp+amp

I would like some advice...

I currently have a Classe SSP800 with a Krell Theater Amplifier Standard (5x200) and a Krell KAV2250 running a B&W 700 surround sound system(703s for the L/R with the matching center and surrounds). I watch a lot of movies, but listen to mostly music; probably 30/70.

I am ready to upgrade and I really feel like my B&W speakers are now the limiting factor. I am interested in going with the Wilson Sophia 2s with the Watch Center. A big chunk of change, but I was blown away by their sound.

I told the sales guy my plan to upgrade and he told me that if I enjoy music the most I am better off buying a good preamp along with a good two channel amp with the money instead of the speakers first. (He recommended a Boulder 810 Pre with the Boulder 860 two channel running in home theater pass through for movies). I can then later upgrade the speakers.

Does this make sense?

Thanks