personally i would keep the wb lambda sensor on there and use the simulated narrow band output for the closed loop control.

that way, the ecu can do it's stuff and you still have a display for the AFR for your peace of mind on boost.

not only will running in closed loop mode give you better fuel economy, by having a cleaner burn it can potentially lengthen the life of spark plugs, make oil last longer before needing a change, prevent the combstion chambers / valve heads / piston crowns coking up which can lead to hotspots creating det.

well worth doing