My E53 3.0i just threw the P1093 code. Just like OP, I used valvoline 5w30 restore and protect the last oil change, about 2500 miles ago.

LTFT's on both banks are between -3 and -4%.
MAF reads over 4gm/s at idle, which from my research, is a little higher.
O2 sensors V on both banks both pre and post are according to spec, except for bank 2 post O2 sensor fluctuates between 0.7 and 0.75 where as bank 1 is constant at 0.77.

I am considering to replace the MAF before I replace the O2 sensors. I hope it is not the CATs.

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06 X5 3.0 Auto ZSP, 06 Z4M, 06 Z4, 06 E83 X3