Stating something as "without question" in this hobby seems quit ignorant. I fancy Audio Research and love the synergy between Manley gear. However, my experience doesn't count in your setup. Yet, I have the Neo-Classic 300B preamp driving the Snappers: and they are just plain beautiful together when it comes to projecting music. After reading the advices, you should probably listen by yourself.
You mention that you seek more body, stage widening and depth. My experience with the Manley 300B preamp driving Snapper is that it excell in portraiting body, 3D presentation and timbre.
Body stage depth
You mention that you seek more body, stage widening and depth. My experience with the Manley 300B preamp driving Snapper is that it excell in portraiting body, 3D presentation and timbre.
Body stage depth