It comes down to: how often is the OP recording "quiet shows" and does it justify the cash outlay for a mic pre? I can't speak for everyone and every situation, but I've found that when stealth recording quiet shows, location in the venue is much more important than additional gain from a preamp. And if you're running 24-bit you have the extra room for raising levels in post without introducing more noise. For me, my recorder and a battery box has provided plenty of gain for the quiet gigs I've recorded; I haven't found the need to invest in a pre for my stealth rig. YMMV.