15) Take your pic put the car on a lift, jack stands whatever you prefer I used 2 ramps and 2 cinder blocks (
<--Safety warning: Cinder blocks are not recommended)

16) If you drive the car onto the ramps be sure to disconnect the batt again
17) Get under the car and with a marker make a mark where you want to position the o2 sensor be sure to put it in an area where it has clearance remember it is about 2 inches long, AEM recommends it to be 36 inches away from the turbo and always before the cat for best results, this is where us catted guys are screwed, there is only one option and that is between the flex joint and the cat, this area is only about 16” away from the turbo but we really have no choice and I personally don’t think the heat will be too hot, hell the first o2 is only about 3 inches away from turbo!
18) Remove the 2nd (in cat) o2 sensor, I used a large adjustable wrench.
19) With lots of extensions, a ratchet and a 13mm socket remove the 3 lower nuts that hold the down pipe to the o2 housing, the top bolt is easy to get to with just the ratchet and socket by reaching from the top of the car, if you have never done this the top one is actually a bolt and the nut has a bent piece of flat stock welded to it (kinda acts as another wrench to hold the nut from turning while you tighten/loosen the bolt)

20) Next remove the bottom end of the down pipe from the rest of the exhaust , if you have aftermarket there is 3 nuts/bolts and if you have stock there is a 15mm(I think) nut to loosen and you have to twist it and slide it apart.

Here you can see that I made a mark on the DP I also marked the cattless DP too in case I decide to put it back on
21) Next you need to find someone who can drill a hole in the down pipe for you and weld in the bung, its best to tig weld it and request the welder to use stainless filler rod (so it wont rust) it would suck to rust a hole in your $1000 B&B exhaust because you used all purpose steel sorry no pics I did this part at work.

22) To have extra precaution I taped off the hole and the flat surface that the o2 housing sits against and painted the area with 2000 degree paint. This is not required but I did it just to protect it.
23) Now you can reinstall the down pipe I put the o2 sensor in first just cause there was not going to be much room to reach up in there after the pipe was on.
24) Reinstall eh stock o2 sensor
25) Locate the o2 wire bundle supplied with the gauge and rout it from the gauge to the o2 sensor that you just added to the down pipe, I ran mine through the boot that covers the steering rod, neatly hide the wires inside the dash,

26) Plug the harness into the AEM o2 sensor and the gauge nest to the first set of plugs you plugged in.

27) This is a good time to reconnect the battery and start the car. You should get a reading from the gauge, depending on weather and temp your gauge should read 14.xx to 16.xx something
28) If you painted the area around the weld like I did follow the directions that came with the paint, IT MUST BE CURED
29) Lots of people skip this step and that’s why there paint burns off after 20 miles my paint I used calls to idle for 10 min then cool for 10 then idle for 20 and cool for 20 then drive it like normal.
30) If the gauge works than its time to clean up and mount your pod, this is where your left with many options
31) You can reinstall the stock pillar and set the gauge pod over it drill a couple holes and use the supplied push clips supplied with the pod, I don’t like drilling holes in my car parts I wanted to keep the stock pillar in perfect cond. So I have heard that one guy used 3m double sided tape to tape the pillar pod to the stock pillar, I on the other hand decided to completely leave the stock pillar off as it opens a huge hole at the dash to run wires for future gauges.
32) I decided to use one one self tapping screw between two of the gauges to hold the pod in place I then painted the screw to match the pod color.
O hope this helps out, feel free to PM me for any questions.