B&W 702 Signature vs The original B&W 702 S2

Sorry, I now realize that the Signatures are the upgrades, not an option to upgrade your S2's. Oh, well. That's an expensive option in my book, but others have taken that route, I'm sure.

This is informative, but doesn't compare the two:
https://www.youtube.com/watch?v=v6-5BR9Sebk

I’ve owned many of the recent B&W speakers, including the 702S2’s.  They were very nice for the price point.  The new 702’s are darker sounding and overall not as good a value as your 702’s.  I also had the 804D2’s,  802D2’s and now the 802D3’s.  The Diamonds are special and once heard, addictive.  I would get the 804D3’s or 803D3’s....both are great but the 803D3’s are a whole other level of wow!

I owned the 703s (order version of the 702s) and I think they are really bad (first “highend” speaker and I did not know any better). There is some thing very odd with the upper mids around 4-5k range. The current 804d3 do the same thing imo. It is just the voicing. They also lack bass and need to be played loud to come alive.
I would try to by a used pair of focal 1028be,1038be, Thiel 2.4CS. All of which will be more natural with more bass than the 702.

Just demo other brands before moving up the B&W line to make sure it is really what you want.