Never saw this thread until now.. but here it goes
I got a backdraft with EFI, got Innovate LC2 widebands in both banks (left and right exhaust, on the outside of the bodywork just past the 90deg bend).
My first sensors failed quickly, but I realised I made a wiring mistake that a lot of people make/have by their supplier.
The 4-oclock position isn't ideal, because condensation of exhaust gasses (that contain loads of H2O) will collect there.
The trick is, to NEVER heat up the wideband sensor before the motor is running. So if you power-on your sensor and controllor with key-on (as I had before) it will get hot with the water droplets hitting it, thermal shock breaking the ceramic element.
Now I have it wired in with my fuel pump relay. Only when the motor is running, will the element start warming up. Because of the exhaust gas temperatures racing through the pipe, the moisture is evaporated in paralel to the sensor warming up, and i've been enjoying my sensors with no issues ever since.