I just got mine set up last night, with A64 3200+. I have the same problem as the other guy with my Mushkin PC3500 Lvl 2... it runs fine at 2-2-2-6 at 200 bus (with 2.75v or more), but it won't save latency changes. I'v read about a couple of people running Corsair at 230+ bus on it without this problem, but not sure if theirs was the "LL" versions. To be safe, raise the dimm voltage, then go back and increase the bus speed, just in case it doesn't save lowered latency settings. If it raises bus speed without lowering latencies, as it does on mine, it might cause BIOS corruption. I think that could be what caused the rampant BIOS corruption on Asus A7N8X's. I've had it up to 220 bus with default cpu voltage, but it needed a little more dimm voltage (set to the max of 2.9, which is undervolted to about 2.85) to run 2-2-2-6 timings. It's fast at 200 bus.
I haven't bothered with the C-box yet, but I'm using the built in sound, and it's pretty good. I think I gave away my installation CD for my Audigy2 ZS when I gave away my Live 5.1, so I can't install anything but basic functionality for it. I read somewhere that Creative robs you of $15 for a replacement CD, while they have only "updates" on their site.