Been listening to Chevelle for the past week. I think some of this will make for good reference tracks for our 2nd album, but for now I'll keep up with what we're doing.
One of the things that I appreciate about their production, along with Andy Wallace's mixes (which are among my favorite for this genre) is how the low end contains clarity, largely in part to the drums/bass treatment, but even with the down tuned guitars. Amp selection/voicing is crucial.
The Boogie Mark IV that Loeffler uses is perfect for this application, which is obvious why it was a choice for John Petrucci for so long considering his 7 string usage.
Using a Boger Uberschaal or an Ecxtasy or a Shiva may have bloomed out the low end on the guitar too much for this application.
I've also dug the anthemic nature of some of their riffs/chorus's.