I've traded two more emails with "Jace" from technical support at Aphex since that first response from Pati earlier. He eased my mind by telling me that the newer rack unit (the Exciter) is pretty much the same as the 204, which was discontinued and replaced with the Exciter rack unit. That's great news because the 204 is such an outstanding unit.
I was just using it minutes ago. I ran my bass straight out into a $30 ART mic preamp (to get the input impedance in a good place) then straight into the 204, then out of that directly into the Mackie FR1400i power amp, then into my cabs. It would be very easy to use the Aphex as one's preamp all by itself! It worked great in that capacity.
My point is that the Xciter pedal is as good sounding and as versatile as the 204, so one could actually get away with running their bass into the Xciter and directly into a mixer or recording interface and see EXCELLENT results. Keeping in mind the Xciter has such outstanding input impedance specs you could easily plug directly into it and come directly out into a power amp, mixer, or audio interface.
I guess that's why they call that ability "direct box".
That Xciter will make an excellent DI.