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01-07-2026LAST POST
This thread will showcase the build and progress of my E91 M3 with retrofits and custom modifications along the way

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by @TheBimmerPlug on IG

Thanks to those before me
63NP's user avatar63NP
BlueM3Wagon's user avatarBlueM3Wagon
LeddyMotorsports's user avatarLeddyMotorsports
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damp21's user avatardamp21

First a 2011 E91 328i
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I've been slowly collecting parts for this conversion as I come across them, I'll mark and photo them below

Body&other
513M wheels ✔
Brembo brake ✔
BC coil-over suspension ✔
Rear quarters ✔
Bumper brackets ✔
Mirrors ✔
M3 rear subframe
Hood
Fenders
Side skirts
Bumpers front/rear
Fender brackets
Headlight brackets
Carbon rebar front/back
Radiator support
Roof rack delete
Auto-open rear hatch
M3 control arms front/rear

Interior
Front seats ✔
Rear seats ✔
Steering wheel ✔
Individual Extended leather dashboard ✔
Individual Executive sun blinds ✔
Dashboard upholstery ✔
Split armrest
Individual Extended leather center console
Anthracite headliner plastics/trim

Electrical
M3 Individual audio chassis harness ✔
M3 cluster
M3 Individual speakers & amp ✔
E91 Individual headliner speakers ✔
PreLCi Headlights
PDC front & rear harness(’s)
Power steering rack (EPS)
Soft close doors


Seats/Door-cards
Shoutout the guys over at thefunyard's user avatarthefunyard
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Misc Photos
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I've put the interior in for the most part, front seats are pretty much PnP if you have the same interior package. Rear bench is also PnP but the backrest and bolsters needs to be re-upholstered onto the E91 backrest as the folding mechanism is located/works differently and the bolsters are shorter.

I've taken some photos and video of some of the process (Not including removal/install from car and headrest removal) for anybody in the same position and wants to take on the challenge themselves.

To break it down I'll list tools and steps below-
Tools:
Sturdy plastic pry tool set
Wire snips
Hog ring plier kit
Leather punch kit
sharp blade/knife

Steps1:
Using your plastic pry tools you want to work your way between the carpeted back of the seat and the leather, prying in towards the carpet you'll see the leather is attached to a plastic clip rail and will slowly come out as you work your way around the seats. (DO NOT remove leather yet)

Step2:
Peel the leather back CAREFULLY around the foam just enough to expose the cover held down to the foam using hog rings and "listing wire".
Wire snips in one hand, pull the cover carefully but firmly exposing and cutting the hog rings. Work you way up till the leather cover is free and do the same with the other backrest portions, base and M3 donor.

Step3:
You're going to need to mark and cut out the holes for the E91 folding mechanisms. I'm not an upholstery guy but what I found to be one of the easier was to simply slip the M3 leather cover over the E91 backrest and cut an X where the mechanism presses up and slowly widen it till the covers fit then using the leather hole punch on the ends of the cuts to keep them from tearing.

Step4:
Once separated and prepped, set you old base leathers to the side and get your hog ring pliers ready. Work the leather cover over the foam insert just enough to get the tension wires in-line. Now while holding the "listing wires" together use the hog rings in the open slots along the wire to hold them together firmly.

Step5:
Now you're done! All that's needed now is to clip the leather back into the backrest/carpet section and install it back into the car.
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I love these and will fully support every conversion, best of luck!
:coolpics:love it
The M3 we all really wanted.

I took the easy way out and bought an entire E90 M3 to make the conversion way easier. ;)
Such a cool conversion!!
This will be an awesome build, just dont put crappy coilovers like BC on the car.