The issue with the internal v-regs is that they aren't always well-sealed (epoxy encapsulation) and are thus susceptible to moisture penetration and subsequent failure. An externally mounted unit or an easily repaired/replaced alternator (such as the GM 180A) is a must for serious off-roading as opposed to our expensive OEM units. At the Ocala meet last June we had three alternator failures due to this issue. Fortunately, all were replaced under warranty.