@ itsnotanova:
What Audi engine are you talking about. There are different 2.7 Audi Biturbo engines out there. Especially if you are talking about engines prior 2001 - they have a lot of problems if they are getting older:
Turbochargers
Y Hose / pipeignition coils
Lambda sensors
Crankcase ventilation system
Manifold
Throttle
Camshaft actuator leaking / broken
F-hose at the engine Conditions
Control lines to the wastegate doses
Exhaust gas temperature sensor
Power Amplifiers ECU
So maybe you can get them cheap, but very often you have to put a lot of money into them.
I would recommend to search some Audi forums.
Regards from germany
Markus