E. The ride would be smoother with C, but not sure it'd be terribly noticeable. The bigger difference is going from highway tires to a/t's. Still, worth it.
Edit: After two days, decided the E are too rough riding for my taste and need, traded in for C K02s still in 265/70R17s. Way, way, way smoother ride. Night and day difference. The whole thing above where I stated, "not sure it'd be terribly noticeable"... yeah, I was wrong.