Cuzoe
Autocross Champion
- Location
- Los Angeles
You are correct regarding ROW and NAR. But that difference is a hardware one. Where the ROW part has (P) instead of the word "PARK" for the parking brake.Thought 791 is for ROW and 891 is for NAR.
and A&B is different hardware.
A and B is different software.
There are a few different hardware variations but that seems to have just happened over time, different revisions. But the important thing is the software. On a new unit, hardware and software number will probably match.
It's a somewhat, but not 100% safe assumption that you can upgrade software from A to B. I did, so I have 791A hardware but now software 791B. It's probably not safe to downgrade from B software to A on 791/891B hardware though... Not that I can think of a reason anybody would be trying to go backwards.