I actually OWN a zeithronix wideband setup. The replacement o2 sensor is about 40 bucks. I have not hooked it up yet, but it seems REALLY nice, and it can display EGT also for 12 bucks, the cost of an F type EGT probe.
It data logs as well, displaying EGT, Throttle Position, Boost/vacuum, and Exhaust O2 levels all vs RPM, so it is really sweet for tuning