Surround Receiver PreAmp Comparisons

Greetings fellow agoners.I Have moved my small home theater system into the bedroom & picked up a stunning pair of lightly used MA Silver RS6's here on Agon.Next up is a new surround receiver that will power an outboard multi channel amp after the rest of the components & cabling are added.I REALLY like the auto setup & room equalization most receivers have nowdays & am wondering if there might be a consensus on whose PreAmp section is the cleanest.Choices in this market include Harman Kardon,Denon,Onkyo,Integra,Pioneer Elite,Marantz & Sherwood Newcastle.Looks like the Newcastle & Marantz would be the toughest to find here or on the Bay.Looking forward to your responses & thanks for your time.