i've been looking at getting a downpipe without a cat because where i live they don't check emissions and i'm pretty sure i could pass it if they did without one but i'm stupid when it comes to all these sensors and everything so where exactly is the 02 sensor and aren't there two of them? also i've read on VFAQ if you dont' have a cat you'll get a CEL light and can fix it by doing something to the 02 sensor so is that fairly easy. i'm wanting to do the downpipe install and everything myself and was needing to know where all this stuff was at and how to avoid screwing something up. and one more thing if i get a 3" downpipe will it fit good on both ends without to much trouble? TIA

do you have a 3in catback exaust... cause if you don't you need to start there first... don't start at the turbo and go smaller always go the same all the way or small to big...never big to small

oh and your o2 sensor is in your o2 housing

ok where is the 02 housing? i feel retarded for asking that but like i said i have no clue about some of this stuff.

open your hoof and look down to the left of the heat shield. You'll see a set of wires run into the exaust. Those are the wires that go to your o2 sensor. If you have a 2g, there's another one furthur down about 12" after the cat. This is the one that can cause a CEL if you run a test pipe. Just plug the bung and tie it up.
If it's a 1G, there's only 1 o2 sensor and don't need to worry.