I recently purchased a 1999 Passat 1.8t for my wife. This vehicle has 17,000 original miles and is in primo shape. Being new to water cooled VWs I was looking for some advice on maintenance. I have read about the plastic water pump impellers that disentigrate but am not sure if I should replace now or wait a few thousand more miles. What about timing belts? Any other parts that are destined to cause me problems. I would just assume replace them in my timeframe rather that get surprised. Thanks.