Vandersteen 5a carbon vs 5a

Is the 5a carbon worth the $10,000 more than the 5a? If you have compared both I would love your opinion and why you came to that conclusion. 
i owned the 5a for five years or so. A great speaker and certainly a hyper good value at the $9-12 K range you see them being sold at....
yes I have heard the 5a carbon as well and find it sublime.
I own 7 mk2 with the M7 amps as well.
the carbon fiber/ balsa drivers are so low in distortion they are something to be appreciated with time......listen for ten twelve hours at a stretch.....amazing fatigue free clear pure water like flow....I cannot describe it...

i am actually thinking of trading my Treo CT ( good as they are and they are good.better treble than my 5a ) for the birdseye maple 5a carbons Sunny has.....

you might hear some 5 a owners making a fuss about not being able to hear the difference....and yet singing Richards praises....
I am 200% sure he is right with the new drivers....
Price aside, the 5A ought to be readily upgradeable to the Carbon 5A.  Or what am I missing?
I believe there are other issues than just installing the new Carbon Tweeters that make it a no go.
I own the Treo's and would really like to upgrade to CT, but it isn't in the cards.
according to review in TAS the upgrade from 5a to 5a Carbon is available only to original owners
I am an original owner of 5A's and was going to send them back for the update.  My wife and I listened to the 5A Carbons and although the electronics were different, and maybe an unfair evaluation - but we both agreed they sounded so similar, it wouldn't have justified the cost.  MAYBE....a bit more clarity in the mids, but not sure.  If I were to buy new, I would probably get the 5A C's, but I'm quite contented with the speakers I have.
The upgrade path is marginally workable with freight both ways, new drivers, crossovers, and the hand tuning each speaker gets in the anechoic chamber - extended to original owners only for a good reason.
good as the scanspeak drivers are, the cost to handbuild the carbon fiber and or CF/balsa drivers is high. satellite grade CF and 3 axis machines balsa are not free.
call it confirmation bias IF you like but the fancy German laser shows the balsa / CF drivers as pistonic and in phase in some cases an order of magnitude better than other top rated mid ranges.
only your ears and budget can discern value....

enjoy the music :-)

Thanks for the replies. Would like to hear more from anyone heard both and feel the 5a carbon is worth the extra in terms of sound.
Any comparison to the Quatro Wood CT?
There is so much talk about Vandersteen 5 ct ,5a, and Quattro ct I can’t believe there are not more options!
more options for ya:

Treo CT with sub 3 = approx $11,500

Treo CT with 2 X sub 3 = $ 14,500

Treo CT $8,500

VLR Signature $3,250 + Soundanchors

VLR Signature + Sub 3 $ 6,250

VLR Signature + 2 x sub 3

regular VLR $1350 ......

3a signature.......

the list goes on !!!!!
I heard the Quatro CT and the 5a C this spring. That tweeter really is special. The mid-range on the 5AC was also very grain free and lovely. I too have been tempted by the bird's eye maple pair. 
Does anyone know for sure that all the drivers are replaced during an upgrade? I know the tweeter and mid-range are, but I'm curious if the factory replaces all drive units.