Does it matter if they came from an AWD or FWD? Or will they be compatible with both?

The AWD has a resistor soldered in position R130 on the board, to tell the cpu it is AWD, other than that they are identical.They are mutually compatible other than a difference in top speed limiters I believe.

I believe the fuel maps might be slightly different as well since the gearing is different. Steve Hill is running a FWD ECU in his AWD without any problems...then again ;)

Alrighty, thanks guys.

I've personally examined the code from AWD and FWDs and, at least in the eprom ecu's, the maps are identical.