Vandersteen 5a, 15 years old vs. new Vandersteen Quatro Wood (upgrade or downgrade)

I currently have a Vandersteen 5A purchased about 15 years ago in great condition. My  equipment  is Thor 150 watt  tube EL-34 monoblocks with a Thor linestage, Sony SACD player and a middle of the road VPI turntable. Was reading about the Vandersteen Quatro Wood CT which I believe retails for $15,000.00. The wood has the carbon tweeter, my 5A's do not. The Quatro also has a 250 watt amplifier for the built in sub while my 5A's have a 400 watt amp.  If I purchased a new Quatro Wood and sold my 5a's would the resulting sound be better overall in my 8 1/2 by 15 foot room?
 My rationale for considering this upgrade, is that I would be getting a speaker with all new parts and would obtain a new warranty.  Any thoughts would be helpful.  In short is todays' Quatro Wood CT a better sounding speaker than my old 5A?  Would this change be an upgrade and would it yield an improvement in sound to justify the cost?

Thank you. 

M