I'll check mine out. Mine is now 2 years old and 50,000 km. I can see how the belt may be a bit worn out, but i think changing the belt and water pump if it looks ok a bit premature on a 2 year old car?
My biggest concern is how rubbish my spark plugs are after only 20,000 km! What kind of cheap NGK's did they put on my car?
As Jrkitching has said plenty of times, its not the plugs fault, it's the ethanol in the fuel, I've done about 7 or 8 k miles since my last service in April or May and I can feel that there's been a drop in performance.
The thing is that with the water pump it's a cheap part (under £30) so you might as well do it while you're there. A water pump failure can cause issues as well
http://www.alfaowner.com/Forum/engi...er-pump-failure-causing-cam-belt-to-fail.html
For the sake of £30 when the belt is off I'd do it. If the water pump does fail then it's all the labour to get the belt off again, the cost of the belt and then the cost of the water pump. Do it once and do it properly.