In reply to ditchdigger:
Having bought well over 100 sensors in my carreer (and using probably 50 more of a different brand), I can firmly attest that if you have one that is good, it will probably stay that way. Unless you cut a line (or melt it), or if the sensor gets damaged itself (knocking the sensor, water on a cold sensor, whatever). Of the huge numbers I've worked with, the failures are about 10 sensors to 3 wires to 1 box as a failure ratio.
The electronics are stupid simple, relatively speaking. IHMO, Innovatre, AFR, WBO2- they all make good stuff. And the sensors they use- NTK or Bosch- are also very good. You'll be happy just having one.
If you are interested in the one from down under- shoot them a note. I've only bought 2 of the basic sensors from them, but they have been super nice. They'll give you the exchange rate and shipping.
(oh, and don't bother asking what I've bought- the cheapest one was $2500... 10 years ago- they are all $3500-$5500 for what we buy).