Rieger Diffuser - Header

BMW 135i – Rieger Rear Diffuser

I finally got around to installing these two cosmetic parts that have been sitting in my garage. I bought the Rieger diffuser used and the carbon fiber hydrodip was fading. Time to get to work!

Rieger DiffuserSanded it down with some high-grit sandpaper and setup a ghetto booth in the shop’s bathroom.
Rieger Diffuser - Spray boothPut down a few coats of primer and then started spraying Plastidip.

Rieger Diffuser - Primer Rieger Diffuser - PlastidippingI put a bunch of coats of Plastidip on and it looks great! The finish is a real nice matte black and it seems very durable. The diffuser didn’t come with any mesh, so I went to Home Depot and bought a roll of black gutter guard. It was really cheap, only like $2 or $3. Cut it to size and hot glued it to the back.
Rieger Diffuser - MeshOnce I installed the diffuser, the exhaust tips were sunk in behind the bumper. Since this is an aggressive diffuser, I had to get them extended. The tips were always a bit crooked, so this was a great excuse to get everything straightened out.

Here is a picture I took shortly after buying the car. You can see that the exhaust tips were melting the factory diffuser because they were pushed up against it.
Stock diffuserAnd here are some photos I took after installing the Rieger diffuser:
Rieger Diffuser - Tips Rieger Diffuser Installed Rieger Diffuser Installed Rieger Diffuser Installed

9 thoughts on “BMW 135i – Rieger Rear Diffuser”

  1. My rear Rieger rear diffuser melted :/. After getting the Ark cat back exhaust installed along with the Rieger rear diffuser a weld on the exhaust broke causing the muffler tips to push up on my diffuser. It melted very quickley along with part of my rear bumper. Ark has since given me a whole new cat back exhaust that I haven’t opened yet due to the idea of purchasing a 1m rear bumper and rear diffuser. If I do that I’ll need to get a custom exhaust done. Have any places you recommend in the area for custom exhaust?

    1. Damon, I’m not sure where you live. I can’t recommend anyone because I haven’t needed any custom exhaust work. Eventually I’d like to cut out a section of my Rieger and run a quad exhaust…

        1. Ah, that’s right. When I’ve needed small exhaust work, I just had my buddies take care of it. You could ask Beyond Redline if they do custom exhaust work. If not, ask them who they recommend in the area.

  2. Looks awesome! Thank you for this website! I am currently waiting to go from my NA6 Miata to an 08 135i! Waiting on the air-bag recall to be performed, then shes mine!!

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