O2 sensors and the EGR

2 quick questions.
1- I have read on here people have cut out their front cats alnong with the front o2 sensors? How can this be done without setting of CEL?

2- My car keeps throwing a #43, which could be the EGR circuit, value and /or seliond. Could this also cause ruff idle and poor performance? the reason I ask is the car worked so well for about a month with this problem, then it really went down hill, no power, ruff idle etc.

Its a 94 svx and without this forum I don't think I would of bought it. thanks for sharing.