Hello,

A couple other things you should look for is.

TPS - Throttle Position sensor
FPR - Fuel pressure regulator
Temp Sensor

Leaky injectors is another comon problem.
Spark plug wires

First thing you should do is have all the codes read. Most VW/Audi repair places has the VAG 1551/1552 scan tool if not you can do it by your self. Have this done first before getting too deep into replacing everything.

http://www.sjmautotechnik.com/ecufv8.html

That should help.

Another good source for info is from:

http://www.audifans.com/

Hope this helps,

Karl K