Oil Leaking Onto Downstream O2 Sensor Connectors

[X5Cat]

While under the X just now, searching for the upstream O2 connectors so I can replace them (just the upstream O2 sensors), I found the downstream connectors drenched in oil (as shown in photo) from a slow, but long-term leak. Wondering if this could possibly be responsible for or contributing to my performance problem.

I've had this issue for quite some time where, once the vehicle warms up after the first mile or two, it jerks and stumbles when I accelerate or when there is a demand for power, like going uphill. Pulled the codes and got the P0430 (Cat Bank 2, I think). Bought replacements for the upstream sensors a good while back, since they were overdue for replacement anyway. But, due to some health and other issues, have just now gotten around to attempting to install them.

Guess I'll know pretty soon if I'm extremely lucky and it turns out the upstream sensors do the trick. Feel like I won't have that sort of luck, though. So, I'd really be interested in knowing what you guys think the chances are that all that oil goo could be throwing off the downstream sensors enough to cause my issues.

One more thing -- I saw in a post somewhere some guy saying I had to clear the DTC's before installing the new sensors. I have a little trouble believing that is necessary. Thoughts on that also, please?

Thanks!