Wheezing water pump

[Kur]

Hello guys.
My Boxster (2.5l, 1999) has developed a wheezing noise a few days ago. It's not unlike boiling water and initially it was pretty faint but now I believe it's become a bit louder and more frequent (or I'm just a bit paranoid). I went to my mechanic and by using a stethoscope he located it to be coming from within the water pump. However he told me I shouldn't be too bothered about it and keep driving it until I can no longer stand the noise. :ah:
So my first question is this really so or I better change it as soon as possible.
My second one is if anyone has had any experience with 'Circoli' brand water pumps which retail for only like 75 UK pounds or I better go for an OEM one which is double this price and which is apparently considered better then the genuine Porsche one.
Any advice would be appreciated.