Seems like a guy who wanted one or the other could probably sell the other half for enough to make the purchase a 1/2 price deal.
I got mine through the other half of your method - got the amp at a good price by buying it from someone who wanted the speakers. Had to pay for the shipping to the other gent, and then to myself as they wouldn't split the deal from the mfr, but I still ended up getting a 35 W/channel tube integrated for less than I figured I could do a DIY project. [disclosure] My HT system is also Onix - that's how I came to hear about the SP3 deal when it originally came out. [/disclosure]
Then admittedly, I got a pair of used Ref1s in Birds Eye Maple (my reason for not wanting the Rosewood finish in the deal was purely house decorating). My rationale for sticking with the original combo rather than trying out different speakers is I figure there will be a fair number of these systems around with that amp and speaker combination. I'm hoping that means there are a body of people rolling tubes on that combination and reporting on what does and doesn't work. Admittedly, personally I'm figuring to mainly stick with new production tubes rather than going on a NOS search, but I reserve the right to waffle on that decision.

IMO it makes a great alternative to my large-everything HT system. Minimal cabling, small, and definitely "cuter." And all that was before it ever got turned on. Then I find the tube sound and more revealing speaker combination is also a nice alternative to the solid state and more forgiving speakers in the HT.
My only nit of criticism is that I'm using it in our bedroom, and IMO the lowest volume on the stepped attenuator could be quieter. I put a lot of the blame on the mastering levels of the CDs, but I don't have a way of changing that. In time, I'll probably either add input attenuators or learn how to internally mod the volume.
enjoy,