Audio Research, next upgrade?


I have been upgrading recently and have had great fun and results. I really like the Audio Research line and I am slowly working my way to the Reference products. I would like to hear what everyone would suggest as the next piece to upgrade, ie CD, Pre, or Amp first. My current system is:
ARC CD3 MKII
ARC LS 26
ARC VT100 MKII
B&W 801
The system sounds great as -is, but always looking for the next improvement.
Thank you
vdosc
One other thought. If ARC still upgrades the VT100 MkII to the MkIII, you may want to price it out and consider doing it. Give Cal at ARC a call. He always has good advice to share. BTW, another upgrade is changing out your 6550C tubes to the new KT 120s. You'll be pleasantly surprised by the overall improvement.
If you want a change, the most significant change (for better or worse) would be to change your speakers. I think changes in your Source>pre>amp will be relatively minor compared with a speaker change.

I honest don't know which of the electronics I would change first for the biggest bang for the buck - I suspect the CD or preamp would be the most noticeable change. I owned the CD3 MKII and thought it was wonderful, I really don't know how it compare to this year's models, but it might have held up very well indeed. I would bring the CD to a dealer and compare it with the latest, if you notice a significant improvement - starting at the source proabably has the most implications throughout the chain. If the improvement you hear is marginal or sideways, perhaps a move to the LS27.