computer
If you have a '98, then no, you cannot simply swap it out and plug it in. The pinouts are different.
With a '99, the emissions controls are different (EGR). It may/may not work properly.
If you have an A4 and the PCM is from an M6, well, it won't work without being reprogrammed to an A4 file.
If it's got 2.73 programming and you have 3.23's, it won't work properly without reprogramming.
So, like I said, it depends on the year of your car and your trans & rear gear...
-Andrew

