Ayre KX-5/20 & VX-5/20 v AX-5 Twenty

You've got some nice equipment.
Do you really have to move to integrated? I can't see how that much space will be saved by such a move.
Though I would consider some isolation bases for the subs (Like Townshend), so you don't p*ss off the neighbors.
Bob

Bob, I use some blue Cardas balanced cables between preamp and amp.  I think I read somewhere that the tighter connection between preamp and amp of an integrated was beneficial.

I use SubDudes under the HGS-15s.

db

I've heard both of the systems you are considering, but not at the same time and not with your Kef's so it's very difficult to provide meaningful feedback for you... however, I remember being impressed with the Ayre integrated.

From my memory it offered everything that the separates did.  My concern would be in the amplifier section since it does make less power than the VX-5.  However, since you are using your Velodyne's for the low end, that makes life much easier for the amplifier even though I see that the Ref Ref's dip down to the 3 Ohm range.  My guess is that you likely won't miss much in going to the integrated unless you are really nit-picking the minutia in your recording.

My other thought is that you may lose a little bit of the "tuning" that your Cardas cables are offering between the pre & amp... again probably subtle.

Let us know your experience if you audition the integrated, and good luck!

I don't have the exact same combo (I have an V-5xe and K-5xemp) and inquired directly to Ayre about making the switch t0 an AX-5 twenty (my concern was whether this was more or less a lateral switch).  They felt that the AX-5 twenty was definitely an upgrade.  

@OP,
I would still think separates would be a better choice. When you think about cramming all that equipment into one case, there are bound to be trade-offs otherwise, why would they exist?
As for interconnects, I would get some Audioquest cables. They work well with Ayre.
When in doubt, call Ayre. They answer the phone.
(If I recall, try to connect with the Operator, as that will forward the call to Ryan. Otherwise, you will most likely have to leave a message).
Bob