Just to let you know that it is possible to reduce the latency timer on the Mac OS X side (with VCP driver) to make communications between the Mac and Pilbox faster.
To make it work, edit /System/Library/Extensions/FTDIUSBSerialDriver.kext/Contents/Info.plist and insert latency timer settings.
sudo touch /System/Library/Extensions
then reboot.
I got about 2.5 speedup doing this, much better, though I had hoped for a bit more as the latency timer was reduced by a factor of 8.