New amp recommendations

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 .....

Pairing a REF 3 with the Onkyo would be like mounting Walmart tires on a Ferrari.A more balanced approach,consider an Audio Research tube amp at the 2K to 3K price point.

I've found a nice used REF3 for a reasonable price. Should I get it? Also, can you please recommend some good, reasonably priced speaker and IC cables? I've heard good things about Emprical Design cables. Thanks.

I agree that matching a REF3 with an Onkyo amplifier is a bit of a mis-match... but who cares. This is a hobby and if you want to give it a try, go for it.

I think it makes more sense to buy a component that you really want (like a REF3) and plan to keep, than buy two components which you know you will flip down the road and possibly lose money on.

What about the smaller ar ls26?