just got my testpipe in mail and their is no hole for the o2 sensor. I was going to put the pipe in myself but there is no hole. is this normal and how do i drill one

 

sometimes the bung is located in the beginning of the mid pipe rather than the cat

bring your test pipe to a muffler shop and ask them to weld in a bung...just get under the car and figure out where you want it...nothing below the 3 o clock position you don't want condensation sitting on it

 

im am hoping that the sensor is before the cat bc a couple of people says it goes into the cat.

 

If it's for a wideband it goes before the cat (working back from the engine) If it's the stock rear sensor, it goes after the cat.

I don't think having it on the cat (or test pipe) is a very good idea if you are still using the ECU to run the car.