Are you throwing any codes by chance? I'm pretty sure that the o2 sensors would be throwing fault codes if it were the case that they are going bad.
The IAT could be bad, not sending a good temp for enough air to mix with the fuel. Use a multimeter to test that. Just do this to test the IAT:
1. Remove it from the car.
2. Probe at outside temp and write down resistance.
3. Stick in freezer for a few minutes.
4. Probe again immediate after removing and write down resistance.
Is there any noticeable change in resistance? If not, then your IAT is bad, which
should throw a code as well.
Do you by chance have an aftermarket intake?
I noticed that your exhaust has SOME back pressure, so that shouldn't be the cause of you running rich. This is currently the problem I am having, I have no back pressure and my AFR is dropping to nearly 11:1 in the higher RPMs.
But yeah, let me know how the IAT test goes.