upgrade Vandersteen speakers

JohnnyR is correct. There is not a single component the same in the later Vandersteens and I am sure you will be disappointed in the new Vandersteens because by comparison they are bright. They don't have the dynamics or the magic of the old Vandersteens. I already made this mistake once. If you like the sound you have now, but want a really big improvement add a Vandersteen subwoofer. This addition is not as much for the bass as it is for the rest of the music. The subwoofer relieves your 2Cs and your main amplifier of reproducing bass and the improvement will amaze you. It's the biggest bang for the buck.

I would see if you could borrow a newer amp from your ARC dealer. ARC solid state amps have come a long way since the early 90's and the D240 mkII. I think that would make the most significant change. I would also check to see if there is any deterioration around the speakers cones.

Those cables are very good and seem to only get better over time. I have tried others on occasion and have always come back to the ARC gray Litz II cables.

Audioconnection is right, I went from 2ci to 2ce,and now 2CE Signature II. The sig II is unbelievable, it's a night and day different. Also here's what Richard Vandersteen said from one of his tech Q and A

"Answer: HELLO MIKE, THAT ANSWER WAS COMPARING A OLDER MODEL 3 AND A NEWER MODEL 2CE. AT ANY GIVEN YEAR THE CURRENT 3 WILL BE MUCH HIGHER PERFORMANCE THAN THE CURRENT 2. THE CURRENT MODEL 2CE SIG II WILL BLOW AWAY AN OLD MODEL 3, AND THE CURRENT MODEL 3A SIG WILL BLOW AWAY A CURRENT 2CE SIG II."

I say get a newer pair of Vandersteen's. I'll admit I'm biased because they are my favorite speaker. But I really don't feel that you can do better. As far as Rrog's comment about being bright, I disagree. Vandersteen's are very transparent. More likely than not, the brightness is due to something in the system and not the speakers.

In 2011 I upgraded from the Vandersteen 1986 2C to the newer 2ce sig2's. The difference was a big ear opener!
The Sig 2's are not bright. Much more transparent than the earlier 26 year old 2C's.