Pass and ARC

The Pass is the surer bargain for longevity, that much is clear.

I own the XA30.5, also paired with a tube preamp (McIntosh c2500).
The pass has been in my system longer than any other piece of equipment and i consider it a "forever" amp. I don't think you'll be disappointed. I've powered several speakers with it and have settled on 94db efficient Tannoys. The amp has way more power than these speakers require. It should have no probelm powering your Klipsch.
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Synergistic would be a nice match with those. Don't see an IC right now but the Cable Co usually has some. If you need a PC there is a killer deal on SR Master Couplers https://www.audiogon.com/listings/lisa24fi-three-synergistic-research-a-c-master-coupler-power-cords... Hard to beat at $190!

Only one problem I can see with this upgrade and it may not even qualify
as a problem. But first- you do not identify what the aquisition cost of each piece would be. Post that and I may be able to offer counsel.

Don’t know about the AR Ref 2 with Pass amps, but I’m pairing the AR Ref 3 and AR Ref 5SE with Parasound Halo A21 and JC2 monoblocks with incredible results - hard to believe. Just incredible clarity, detail, resolution, imaging and soundstage with superb tone, tenor, texture and bass control - a very holographic, live sound.

I’ve been surprised by this combination - though, I suppose some of the credit must go to the Bryston BDP-3 & Schitt Yggdrasil DAC, which sound superb, even without the AR tube line stage - but, the tube line stage improved upon that combo even a great deal more. And... with either the Harbeth 30.1’s with Townshend Super-Tweeters, or Linkwitz Orion’s - to the point, that I doubt I could improve upon the sound a lot more. I’ve also been surprised that this combo has really awakened the 30.1’s, which initially hadn’t impressed me, but now have much better highs, resolution, and bass control with the Harbeth rich, organic sound.