Ok, so I e-mailed the manufacturer on these scanguages on the VATS issues. This is what I got back (after 5 days of waiting
The only problem we have seen with VATS is a conflict that sometimes occurs between it and the CAN protocol. In 2002, the SAE added CAN to the allowed OBDII protocols. To do this they assigned pins 6 and 14 for CAN. Before this, these pins were not assigned and the OEMs were allowed to use them for whatever they wanted to. GM had been using them sometimes to set the clock and others for the security system. This situation created an occasional problem.
We can supply a special "non-CAN" cable if this is a problem. Pins 6 and 14 are not connected in the cable.
Sounds like they should be ok, but if you use this on a 2002 and newer car, you might want the other cable...