If the TX-RZ70 comes in at close to three grand, that's going to be a tough sell for me, even if it has 11 amplified channels and will process 13 channels.
Considering you can get a refurbished Denon AVR-X6700h for two grand, and it will process 13 channels, you spend another grand on an external amp to power the L/C/R, you've got yourself a hell of a setup. You wouldn't have Dirac on your 13 channels, but if you spend enough time playing around with Audyssey MultEQ XT32 + REW, and run the subs through a miniDSP, am I really going to be missing out much?
Denon Factory Refurbished
www.accessories4less.com