That's my understanding as well, as long as the MAF is calibrated for the proper diameter of intake system A/F ratios should not be of concern...
Front O2 extensions have been removed. However, the code is still popping up once tge vehicle completes the emissions readiness cycle. Any possible issues from swapping the position of the front O2 sensors, I know the LT directions stated to mark which location they were in.
I just got off the phone with Brenspeed a few minutes ago and asked what is changed tune-wise when using longtube headers. Basically the ECU needs to be corrected for the change in the FRONT O2 sensor locations(having been moved back a few inches) so there is something tangible. A/F ratio/timing all those things stay the same, but there are calibration changes so I would get that checked by BAMA ASAP.
Also Aaron make sure all of the pins are undamaged in the O2 connectors, just for grins at least.