I can recommend NOT buying a PreSonus FireBox.

I have issues with crosstalk between playback channel and input channels (even with all output playback devices disabled), and a high frequency whine.

Make sure your chipset for firewire IEEE 1394 is Texas Instruments. Otherwise, you might be setting up yourself for trouble. Check with the soundcard manufacturer for an approved list of chipsets that play well with their particular card(s).