A $45-50K S7 would only make sense if the Q3 upgrade(midrange,tweeter and X-over) took it to $65K.
I think the S7 will dwarf the Q3. From the photos, it looks like it may be about the size of the M Project. The tweeters are all about the same height off the ground. The S7 has a mid driver above the tweeter, just like the Q7 and M Project. I think it will be a big speaker and more expensive than the Q3 which only has three 7" woofers. The M has three 10" woofers, and it looks like the S7 will also. I think the S7 will be priced between the Q3 and Q5, perhaps $50-60K.