New exhaust questions
 

I've already bought and installed a borla cat back exhaust. Now i was planning on buying the racing beat headers and presilencer. My question is what happens to the o2 sensor thats in the headers? I thought without it put in the check engin light comes on? Secondly im in the process of removing the ACV. I bought the plate that goes behind the ACV but how to you block the hoses that go to the back of the engine?
Thanks in advance

also does removing the ACV have and negative effects on the engine?

there is a o2 bung on the racing beat headers