New amp recommendations

Some additional background and input: the size of the listening room is approx. 450 sq. feet, music that I listen to is pretty much everything other than metal and rap, budget: max 5k. Thanks!

I think a Parasound A21 will work great for you. It will save you $$$ for more music and other accessories.

just to be contrarian, (unless of course you want to sell it to me) i'd be really reluctant to replace your integra amp--it's a fantastic sounding piece which would cost something like $8k in today's bucks. to be honest, i've only heard it paired with pre-amps of similar vintage (like the integra 308), and i haven't heard it with your (excellent) proacs so i can't recommend a specific modern preamp, but at your budget you can afford to experiment a bit (tubes? passive?). kbarkamian's idea for ARC makes some sense.

What would you think of pairing the integra with an ARC Ref 3? In addition, do you think that Audience AU24 cables could be a good match?
Thanks.

5k in what currency ?? US$ ?? £ ?

Moon integrated in your bracket is worth checking out. Or if you can find one at a discount the Gryphon Atilla .....