I'm looking to buy a wideband o2 sensor, preferably digital(their all digital aren't they?).

I was wondering, which should I get? What is the popular one that you dsmer's are using that works the best? I got about $300 to spend on this, kinda wanting to stay within $200-250 though. any opinions and/or links would be great, thanks!

also, is it true that the probe has to be mounted into the exhaust manifold right in front of the number 1 cylinder? I have the evo3 exhaust manifold and it has a little hex nut/bolt on the far drivers side of the manifold. I heard that the probe is supposed to go there for the most accurate reading.