I have replaced both my O2 sensors in the wagon in Aug 2011.
Runs great with the new ones.
I know one of them came from Car Quest Auto Parts. $80.00, I called from work in the morning, said they would have one by noon time. Other places wanted as much as $200 + and up to 3 weeks to get one.
To be honest I can't remember where the other sensor came from it's been to long.
174,000+ miles, 5/20/12 new ej257 short block, 8/20/11 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. Also CHECK YOUR OIL, these cars use it.