Hey, Madaradio,
I use a 415M for bass (Dan Armstrong, P-Bass and fretless P-Bass) with a 200S head. Sounds great -- much better than my 215 Sorado enclosure. A few months ago, I hacked around with some friends during a trip to Ohio and put my Nastycaster and my Dan Armstrong 6-string through it. I was amazed at how good these guitars sounded with the four 15's. Plenty of highs that I didn't expect, and the dirt was even better - all without pedals.
Excellent enclosure.
Warmest...