If you have catted downpipes, why do you need O2 sims - I have AR catted with all the O2 sensors installed and it passes OBDII smog check no prob.
Do you really mean you have catless downpipes?
2008 E93 335i, MHD, HPF IC, Injen Intake, AR DPs, Alpina TCU Flash
2016 X5 M-sport 35i JB Stage 1
2013 Mercedes C63 AMG, ROW airboxes, power pipe, Eurocharged V6 Flame tune 540 HP