Hello I will help you with your question,
You only have one bank on your engine and the #1 O2 sensor is the one at the junction of the exhaust manifold closest to the engine.
If you have vacuum leaks on the intake or exhaust leaks you will get this code.
It may be that the sensor needs to be replaced but if more oxygen ends up in the exhaust from the modifications you have made you will have a tough time stopping the code from setting.
Let me know what I can do to help you with this