E46 M3 CSL Diffuser Installation Guide

Installation Tips & Self Installation Guide

To ensure a perfect 10/10 fitment we highly recommend dropping your E46 M3 off at a competent body shop which is fluent with aftermarket modifications.  That being said, a high percentage of our customers do the installs themselves with no issues whatsover.  We do not and will not accept returns on parts damaged while they are being installed, most body shops take responsibility for damages on their clock, so if you have never done body modifications we recommend taking your car to a shop.

Method 1 for 10/10 fitment.

Your bumper is high flex plastic, it should be removed or loosened up so it can flex around the diffusor for 10/10 fitment.  Since both the diffuser and your bumper have a bit of flex to them, you will be able to perfectly line up the two parts together.  Only hand tools are needed for this installation process and most of our customers have done it this way with great results.  We highly recommend bumper removal to get the best fitment.

This only takes about 15-20 minutes if you’ve removed your bumper before, if you take your time and don’t get flustered you will get OEM fitment easily and save however much your local shop decides to charge.  The diffuser is high quality and can flex decently as long as it’s not around freezing outside, same with the bumper, so you have quite a bit of ‘leeway’ while installing it wihtout it breaking, cracking, or becoming damaged.

Method 2 for great fitment.

Using basic hand tools and a floor jack, slightly loosen the bumper, but keep it on the car, and install the diffuser.  Our diffuser uses OEM mounting points so it’s very easy once you have the bumper loosened up and you can see even a few inches below the car.

Method 3 for easiest installation.

Remove your OEM diffuser and replace it with our CSL Style Carbon Fiber Diffuser without removing or loosening up the bumper.  A few of our customers have done this and we feel that by using other processes the over all fitment is much better.  Doing it this way will get the diffuser on your car but without increasing the flexibility of the bumper, you may not be satisfied with the final apperance.

Other installation information:

As with all aftermarket modifications, a bit of time may need to be put into fitment to give it an OEM appearance, most of the time these diffusors go on and fit perfectly, but sometimes ten or so minutes invested will make it perfect – nothing that you will spend hours upon hours on like our competitors Diffusers.

4 thoughts on “E46 M3 CSL Diffuser Installation Guide

    1. Valentin

      Yes you can, but youd need to have a m3 bumper in order to install the diffuser because the stock bumper on the 330ci doesnt have a diffuser as it is a dual exhaust setup. And in order to use the diffuser you’re going to need a m3 bumper and a center quad exhaust just like the e46 m3

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