Which surr/proc to go w/ Krell & Thiels?

I'm looking for advice? I have a Krell KAV-250a3 (3 ch. amp) w/ a pair of Thiel 3.6s and a Thiel MCS1 for the center. I'm looking for a multi-channel preamp processor that would give me balanced detailed sound without brightness. My price range is 2,500 to 3,500 used. Here's what I've currently looked up: Krell Showcase, B&K ref 50, Aragon Stage One, Anthem AVM-20, Lexicon D-8, Rotel RSP-1098, Arcam AV-8 and the Classe SSP-60. Have I left any out...yikes, too many choices. I'm curious about the Lexicon but there's no dealer near me. I'll most likely purchase the Marantz DV-8400 universal player for this system. I listen mainly to jazz (be-bop to fusion), rock (Joni to Zappa) and all types of 20th century music (Reich, Stravinsky, etc). Oh yeah, the back surround speakers are Merlins (2 way) with a Parasound 200 watt amp. Each are about 10 years old. I would appreciate any advice? thanks for looking...