If you don't have the history on the car it is strongly advisable to
change the T belt, water pump and tensioner. It will require a special
tool to hold the dampener pulley. You may be better off having an
independent Audi mechanic do this. Do not trust a mechanic that is not
known for working on Audis.

If you are having random electrical problems with windows, sun roof ...
Check the wires where they go through a rubber protector into the
drivers door. If the dash lights are not working check for worn wires in
the bundle at the drivers side trunk hinge. Don't trust this if it looks
good. Cut it open and look at each wire.

If it is an Automatic change the trans fluid and filter.

Only use Pentosin to fill the power steering power brake hydraulics. The
brake fluid reservoir used regular DOT 3 or 4.

The T44s are great cars but you will need to stay current on maintenance

A great resource for all technical information on the T44s is:
http://forums.audiworld.com/v8/

You will be much happier with a manual.