The correct thing to do is a leak-down test as you will find the extent and location of the problem cranking speed alone has a huge influence on compression tests
Engine Leakdown Test
Beyond getting an overall picture of engine condition, the leakdown test is an excellent way to pinpoint where engine problems are before tearing down the engine. Listening for where the air is escaping by ear can isolate the problem.
Intake Valve: Air whistling out of the intake, carburetor, or throttle body indicates leak at the intake valve.
Exhaust Valve: Air heard hissing out of the tailpipe, turbocharger, or exhaust manifold means an exhaust valve leak.
Piston Rings: Whistling or hissing out of the PCV valve, oil filler cap hole, or dipstick tube means the air is pushing past the rings. Suspect ring or cylinder wall wear.
Head Gasket: Air bubbles in engine coolant seen at the radiator filler cap could mean air escaping into the coolant past the head gasket.
Cracked Cylinder Head: Bubbles in coolant or coolant being pushed up out of the radiator neck can also indicate cracks in the cylinder head or cylinder wall
From what i have seen and A4 can be run pretty far into the ground and more or less just reach a its NOT gonna run anymore point as for example mine came with a 40 year old distributor cap