For what it's worth, a friend of mine recently replaced a Rotel RSP-1068 and RMB-1075 combo with an SR5005, triggered by an intermittent fault in the 1068, and both he and his wife found the SR5005 to sound better than the 1068. I was also pleased with how it sounded when I went over to help get it dialed in. It's a very different animal from the RR2150, as things like DAC and DSP both contribute heavily to how it sounds while the RR2150 is an analog-only beast. Still, the fact that the SR5005 (with benefit of more modern DAC's, DSP, and Audyssey) had an overall good enough performance (including amplification) to not only match up with but even beat a set of 2004-vintage home theater separates impressed me - especially since the price was a lot lower for the SR5005. It suggests to me that the SR5005 could pull a similar trick when matched up against a 10+ year old Marantz receiver like your 8000.
I also recently did some speaker auditioning with one of my wife's co-workers, and ended up getting a listen to some current Paradigm Monitors. I owned some Paradigm Studios for many years and really enjoyed them, but I was still pleased at how good the Mini-Monitors sounded when powered by a fairly unremarkable older Sony surround receiver (list price of around $500 in a dealer showroom). I do think that the RR2150 could, if paired with a good analog source, do more than the Mini Monitors can do justice to, but the Monitor 7's and CC350 are still a pretty nice front sound stage for a surround system. And for what it's worth, my RR2150 has been very happy paired with a pair of Outlaw Bookshelves and an OPPO Digital BDP-83SE. Lots of fun...