e30

O2 sensor help

I just got vrsf catless downpipes installed. I went easy on it, then when I did wot i began throwing codes 2c6a, 2c7e, 2c7f as well as inactive codes 29f4, 29f5. I reset the codes, since I've only had 2c7f come up once, reset and gone since. But my inactive codes 29f4 and 29f5 won't seem to go away. Are my o2 sensors plugged in backwards or in the wrong place? Thanks in advanced!