Wideband installed, seems to run a bit rich

Installed the PLX Wideband today in the Spirit R/T. Based on other experiences here, I installed it in the factory location and use the narrowband output to feed the SBEC. Not sure if this is causing it to read improperly or I have another issue.

At idle, it reads 11-12 AFR
At cruising, it reads 13.5-14.2
At WOT, it dives to 10, the lowest the gauge will read.

The car feels fine and as fast as usual, so I'm a little perplexed on it.

Thoughts?

Are you sure you have it properly set up in MPTune for your cal?
Although that won't change what the wideband reads on its own display.
But you should make sure you have the correct min/max on the WB2NB function.

Actually running stock electronics. The wideband has a narrowband output.

Sorry, I guess I misread!
The at idle AFR is after the engine is fully warmed/the fan has cycled on?

Grounding at battery?

Yes, readings taken after fan cycled on.

Not grounded at the battery, grounded to chassis under the dash where the controller box is mounted.

Ground it to the battery and see.