I found this on the net. Anybody have any idea if it's true or necessary??
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"This happened to my brother's engine this week. He has a 2005 Mark V Golf GTI. The problem is a fault with ALL Mark V engines. There's a gauze filter in the oil pickup pipe going from the bottom of the engine to the oil pump that gets completely blocked up. Even if you're Golf is not showing this fault at present, it may be starving the turbo of oil anyway (if you have one).
Solution: Drain oil from engine (remove bung in sump), before you remove sump, there's 3 bolts that go through the gearbox housing into the sump. Remove these. Remove sump (Allen key). There's no gasket between sump and engine. Rub old sealant off rim. You will be able to see right up into the engine at this point. There is a small pipe going from the oil pump into where the sump was. This pipe is normally sitting in the oil and it sucks up oil from the sump into the oil pump when the engine is started. The pipe is fixed to the oil pump with one Allen-key head screw and a rubber O-ring. Remove this and take off the pipe. The gauze filter is at the end of the pipe. Try and get a replacement from a motor-factor. Alternatively, you can clean it out well using petrol. Clean the sump well with petrol."