B4 ground straps

[Jsandwith0]

Hi guys first post here.

Just got a 2002 B4 thats had a 3 inch exhaust installed and it looks like a custom one.
With the ground strap that is on the upper of the passenger strut tower where does that connect to it has been disconnected.

https://imgur.com/a/tyfgQFp

Also have an issue with the Pre-cat/front o2 sensor being open circuit only when cold, thinking possible ground issue.
Other than that the timing belt has been done and full coolant flush, just needs an oil change.