370z Tuning/Hi-flo cats - Check Engine

[DFVF370z]

Hello everyone! I'm new to this forum.
I have a 2016 370z done some exhaust modifications and I am super pleased with the sound but now I'm getting an engine code.

I have installed a Cat back exhaust from Fast intentions
with AAM COMPETITION 2.5" HIGH FLOW CATS

I am getting a engine code from the O2 sensors post Cat, I have tried the O2 senors extenders (high quality ones with different tip sizes) I have tried all 3 tip sizes that come with the extenders but still get the code.

I was recommended to have my car tuned or my highflo cats will be damaged over time but all the shops I call in the area don't work on Nissan.

Does anyone know a shop that tunes Z's in Vancouver B.C. or anywhere with in a 5H drive Canada or US ?

Thanks!