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Deleting Shadowline Trim on the G8X M3

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Perhaps the biggest sin of the G8X M3’s design isn’t the front-end, but the entire lower portion of the car. Painted Jet Black, BMW calls it Shadowline Trim, and when you order the car you can spec even more of it in terms of a rear lip spoiler and mirror caps in black.

Well, I hate it. BMW does it as a way to save production costs and ultimately hide the visual heft of the car from the side, but to me it looks cheap on a car that costs upwards of $80,000. The M2, M5, X3 M…no one else gets it. Just us.

No more. I’m going to get rid of it. To do so, I’m heading to Tyspeed. Again.

Before we start, yes, I know that includes the black gloss trim around the windows. That’s fine and is staying. Also, I’ve done the fender trim myself, and you can find the tutorial for that here.

Options for removing Shadowline trim

There are two routes you can go. The first is to simply paint them, as you can see on this example.

G80 M3

Looks great. But the more I thought about it, the more I realized what the issue is: the G8X is a big car. This adds to the heft and makes it look slab-sided when uniform in color. Also makes it look a bit like an M340i from the side, especially in Portimao Blue. Still, I almost went this route.

I’ve already explained why I don’t want to choose an Adro kit, so that leaves replacing the rocker panels and rear diffuser with carbon fiber. We can go with the shape of the original panels, or go with the M Performance variant, which has cool little tailplanes like an F-16.

The car already looks like an angry puffer fish, so let’s make it even meaner.

Installing the carbon fiber rocker panels

I’m getting this entire setup from NW Carbon Haus. Opting for true BMW parts here will triple the price for no substantial increase in quality. And since these are all going to get beat up over the course of driving, replacing them won’t be as painful an experience.

NW also gives you all the rivets you need for installation – these are a one-time use element.

We’ll be working with Tim at Tyspeed today (thanks Tim!). The car cannot be on a regular lift here, as we would block access to the rocker panels. Instead, we put it on the alignment rack.

M3 carbon fiber rocker panel
These rivets must be removed along the bottom first.
M3 carbon fiber rocker panel
Next, Tim uses a trim tool to unlock the clips along the top of the panel.
M3 carbon fiber rocker panel
You can start from either end. An entire beach lives in the bodywork, apparently.
M3 carbon fiber rocker panel
The trim off the car.
M3 carbon fiber rocker panel
Install in reverse, an easy process. The new rocker clips in along the top.
M3 carbon fiber rocker panel
Make sure it’s all aligned before snapping everything back into place.
M3 carbon fiber rocker panel
A plastic rivet tool is used to push the new rivets into place, and clip off the middle
M3 carbon fiber rocker panel
The entire process takes about a half hour. It’s one of the easier body modes you can make.
M3 carbon fiber rocker panel
The other side is identical.

Installing the rear diffuser and trim

Initially, I thought that the rear bumper could stay on the car, and if you’re simply replacing the diffuser, it can. But the Shadowline Trim around the edges can only be released from the inside. Luckily, taking off the rear is much easier than taking off the front end.

M3 carbon fiber rear diffuser
The M3 can now go on a regular lift.
M3 carbon fiber rear diffuser
The rear wheels must come off.
M3 carbon fiber rear diffuser
You’d be surprised at how few bolts and clips actually hold it all together.
M3 carbon fiber rear diffuser
M3 carbon fiber rear diffuser
The cover comes off in about 10 minutes, making it much easier than anticipated.
M3 carbon fiber rear diffuser
These clips in the rear make it impossible to remove the Shadowline trim without taking the bumper off.
M3 carbon fiber rear diffuser
The new carbon trim can go on with the bumper off, but the diffuser itself should be installed after the bumper is replaced.
M3 carbon fiber rear diffuser
Adam comes over to assist in placing it back.
M3 carbon fiber rear diffuser
To clear my larger exhaust tips, the diffuser needed to be adjusted a bit.
M3 carbon fiber rear diffuser
This is the “V2” Euro style, which is what the M3 gets in Europe. It does not entirely clear the stock bumper trim.
M3 carbon fiber rear diffuser
Because of that, the diffuser is only 99% flush with the new trim on the sides.
M3 carbon fiber rear diffuser
The tips needed to be adjusted as well.
M3 carbon fiber rear diffuser
All set.

Installing the NW Carbon Haus rear winglets

NW Carbon Haus rear winglets
These can be done at home.

I had planned on doing a separate tutorial for the small rear winglets, but they are so easy to install that I did not deem it necessary. You can put these on without a lift, and they take about 20 minutes.

  1. Release the six plastic rivets (three on each side) with a trim tool. Unlike the side rocker panels, these rivets can be reused.
  2. Place painters tape along the top edge to prevent scratches, then pry with a trim tool along the top edge, from front to back. It might require a little muscle.
  3. Clip in the new carbon fiber winglet, pressing in along the top edge, again front-to-back. It’s ok to use a bit of force.
  4. Reinstall the plastic rivets. You’re all done.
NW Carbon Haus rear winglets
Remove three rivets on each side.

The big reveal

g80-m3-carbon-fiber g80-m3-carbon-fiber g80-m3-carbon-fiber g80-m3-carbon-fiber g80-m3-carbon-fiber g80-m3-carbon-fiber

This kit ties everything from the front-end together nicely, and it looks much better without all that pointless Shadowline Trim.

I think the rear diffuser’s minor misalignment is a non-issue. You may only see it in person because I point it out here. Perhaps staying with a “V1” stock shape is better. But for a third of the price, NW Carbon Haus has products that look as good as actual M Performance Parts and save weight (I’d guess, between all the modifications, the car is about 20 lbs lighter).

What’s next? New parts are already inbound. Stay tuned.

I will tell you this. A Tesla Model 3 Performance pulled up next to me at a red light and proceeded to vanish into the distance. I didn’t even try to keep up. My big nose, stick shifting, dino-burning, straight-piped, carbon-finned M3 never stood a chance.

Who do you think had the bigger smile on their face?

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