I am informed by Scott Kormeier at Loki Research that
1) The ARTS 2 flight computer is no longer available; and
2) Ozark Aerospace has close its doors.
There yet exists this link:
DO NOT ORDER FROM THIS LINK
Which took my order for an ARTS 2 back in May. I daresay it will take yours now (?), BUT YOU WILL RECIEVE NO INSTRUMENT.
I don't know if I was charged. (I suspect I wasn't) Will find out this weekend at the bank.