"Is this a no brainer and an upgrade from the Nordost Purple Flare speaker cables, despite the near lateral move cost wise?
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The only no brainer here is to just stop. I don't say it to be mean, but just so you don't go and spend any more money on expensive stuff that won't make your system sound much better than it already does.
I read your original post again and may have a solution for you. I noticed you are in NJ. Get rid of the Nordost if you can. Then just go to or call Audio Connection in Verona. He sells everything you have so he knows it very well. And just ask him for speaker cables that will match well to your speakers and amp. I suspect you can get something like an Audioquest Type 6 or 8 and spend about $100-$200. It will probably sound just as good, if not better than the Nordost. (Just to be clear, I'm making the recommendation in the context of the OP's system. I'm just saying I think the AQ is better for the OP in this application, that's it.) If he happens to recommend something else, that's OK too. He knows what he's doing, and more importantly, you can trust him. I know from experience.
One last thing. You seemed to be concerned that your Rotel gear was about 8 or so years old. Don't be. For the money, you still can't do better. I listed my 1072 on Audiogon for a very high price and it was sold and paid for in under 5 min. I'm still sorry I got rid of it.