P1093 SEARCH FOR A FIX CONTINUES...

[Fortress]

Not sure the proper way to bump this issue back up but here's a follow up to my previous string of posts " catalytic converter diagnosis help ".

I've been chasing down this pre cat fuel trim too rich bank 2 code for a while now to no avail.

So far I've done:
MAF
Secondary MAF
DISA valve removal, clean, inspect checks out ok
ICV clean, checks ok
Vacuum lines, all ok. ( no smoke test but vacuum leak would show a lean condition vs my rich condition as discussed in prior posts)
New plugs
Swapped coils from bank 1 to 2. No change...
New valve covert gasket ( not related but could introduce unmetered air)
Fuel pressure test at the rail ( shows ok, 50 psi, and holds pressure)
New pre cat bank 2 O2 sensor
All O2 sensors voltages show normal at idle and at speed.
Cat temps show normal pre and post cat ( testing with a laser temp gun)
Previous owner says ALL 02's replaced at 100k, ( car has 118k now)
Previous owner says 1 or 2 cats replaced at bmw dealer at 100k
Live data fuel trims both short and long term show normal.
In fact EVERYTHING shows normal on my Lemur code scanner from BAV Auto. It supports most of the pertinent data live. As I watch the live data via Bluetooth on my iPad both cold, warm, idle, hwy speed, etc. with a seasoned mechanic sitting next to me he says all looks like it should.

The interesting part is that I tracked down the previous owner, and he was hugely helpful in explaining that the check engine light that's been on for YEARS! Holy! He said the car drove fine, showed no issues, same as I'm experiencing. He's a car guy and explained that he didn't want to continue to have the dealer throw parts at it at when the car seemed fine, sans the light. Said the dealer and indi's couldn't figure out the exact issue, and they too concurred the cars "fine"..

Only thing I haven't checked is fuel injectors. I am going to swap bank 1 to 2, and install new O rings. Any other injector tips short of throwing new ones in?

I'm thinking this thing might need a reflash of the DME? Given the previous owners comments, my findings, and with all these dealers and indi's scratching there heads as well. Any suggestions? Cost to re flash? I figured that's a dealer job vs all the threads I read on diy software?