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So seeing as I apparently had an exhaust leak in the engine bay I decided to get to the downpipes and make sure everything was on tight and while I was at it I'd try and get rid of the check engine light from my catless downpipes. When I began I thought I'd take some pictures and see if it would help those who have some interest in replacing their downpipes as I did basically everything you'd need to do to replace them.

First step was to take off engine cover and remove the 8 bolts(use a torx T25 bit) on each air box:

After all the airbox bolts are out take a flathead bit and loosen the clamps on the rubber coupler:

Then you can pop the lid off the airbox and turn it around to get to the two Maf sensor bolts:

Next slide out the Maf sensor and place it carefully to the side and put the lid away to reveal the air filter:

To get the bottom of the air box out first push back this rubber piece back carefully it comes right out:

Once thats done you can pull the filter holder out and see where the airbox sits on two other rubber bits just pull them out:

Here was for me the hardest part of the whole thing, Now the air box is ready to come out but its still attached to the tube that feeds it. It has a little tab on the side facing outward that needs to be pushed in while pulling the airbox backwards. I didn't want to pull the tubing out of the coupler in the front so you need to be careful not to pull the airbox unless the tab is pushed in. I couldnt get a good picture of it but here is the tab on the airbox so you can see what i'm refering too:

Heres what you left with after that last step, repeat the process on the other side:

Then pull out these two sensors on each side by just taking them out of the holders:

And after that unclip the square connector which goes to the primary 02 sensor:

Theres a black bracket that holds the wiring in place, thats whats next so remove this bolt:

And theres two more that are removed with a deep 14mm socket:

Heres the bracket out and the heat shield exposed:

To get the heat shield off you need to first remove a bracket that hold the wiring in place on both sides of the heat shield. Its a terrible picture(like all the rest) but you can see the two recessed bolts that hold it in:

It just comes out now:

Now its easy to get to the heat shield bolts(3 on each side):

The car was still very hot as I started it as soon as I got home so I put on gloves at this point. The head shield is ready to come out so pry it up and backwards to get it out. The reason we unclipped the square primary 02 sensors earlier was so we could get the heat shield off now:

Finally the turbos and downpipes are exposed. Since I was looking for a leak and not replacing the downpipes I took a wrench to tighten the primary sensors:

And pulled out the two back secondary O2's which are the cause of my CEL for my trickery:

I started at 4:42 and got to this point in 37 minutes. While this isn't a complete DIY for the downpipes(hence the title) really 90% of the work is done. From here you'd remove the V-Band, jack the car up and loosen the two bolts on each downpipe and they come out thru the top. Then reverse the process and your good to go, I really think that you couldn't take more than 3 hours for the whole thing and if you have access to a lift its even faster. Here is the rest of what I did.

I'm putting two spark plug non foulers on each O2 sensor. One is drilled out and screwed onto the sensor and the second is left alone to cover the first one. The purpose of this is to get the sensor out of the direct path of the exhaust to reduce the amount of emissions that reach it and make it believe the cats are present and working.

Heres one drilled out and one intact:

Then it screws back into the DP and put everythink back together.
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