I talked to my tuner. I told him that since my last dyno tune I'd installed a JLT intake and he suggested we stick the WBO2 sensor in the downpipe and verify the state of the tune with the new intake, especially at idle. Then we can up the idle to 1000 and install the factory H-pipe and retest it. If all goes well, I'll put the MRT back in and bump the idle back down to 750 again. I'll post back when I have results.