Back to basics.

Back to basics.

"In this Special Series, I document my experiences with a Vorsteiner trunk, and why it prompted the development of a new E92 CSL Carbon Trunk made in Germany.

In this entry, we start with the basics. I cover my unboxing impressions the E92 OE+ Carbon Trunk. It is both a stand alone product, and will serve as the basis to develop the CSL signature ducktail. "
- Matt

Trunks are a PITA

Developing a new trunk mold is expensive as it is composed on multiple sections making up the complete part. Furthermore, the market for this type of CSL design is limited and to make matters worse, the sedan and convertible each need their own molds.

Lastly, the market size is further trimmed down when the quality targets I aim for need to be met: OE level fitment with complete carbon construction. 

Projects thus need to be de-risked and this is where it starts. The basics: welcome to mold-economics.

A German connection

I have been working with this Germany manufacturer. since January '22 - he's a classic German: a tough nut to crack - but once you're in, you're in. Most known for its curated parts in the E46 exterior programs, I've brought his madly impressive 1:1 CSL bumper and widened carbon fenders to the North American market. 

You have seen their parts branded under various German tuner brands. He notoriously makes these E92 motorsport carbon doors branded under a half a dozen names. 

We've mostly recently collaborated to develop new M3 V8 parts including the recently recently released widened & vented front fender kit

We got lucky. 

A part of Sascha's mold storage included a 15 year old mold. Back in 2008, when the M3 V8 had just come out, he developed an OE+ carbon trunk for motorsport customers that wanted an OEM look without being hassled by legislations. 

The result was this: a complete carbon trunk that look straight from BMW's factory. He painted & installed the GTS wing for his customer as well as adding reinforcements. 

We doubled down on our luck. 

Another hidden gem in his back catalogue is a CSL style E82 1M carbon trunk. From my perspective, this further derisks the E9x M3 CSL carbon trunk project considering Sascha has actually done a CSL style ducktail before and it looks proper. 

The ducktail is much sharper than on my Vorsteiner trunk. I like it - it looks far better. 

The E92 does have a wider section on the quarter panel to design for. It won't precisely be like the 1M. 

This is where it starts. 

This 15 year old mold was serviced and put back to production spec in early August as Sascha and I discussed bringing a new CSL trunk to market. I offered to derisk the CSL project by commissioning a trunk for my car out of my pockets. 

My Vorsteiner DWVP CSL trunk is not only discontinued, it just wasn't good enough for me. We needed a whole new base.  

My intentions are 2x fold:


The immediate goal is to curate this trunk as a valid option available now for any E92 owner that wants a super lightweight trunk with OE fitment.


The ulterior motive is showing the M3 V8 community at EuroConnex how good this trunk is to kickstart a crowdfunding campaign for a new, proper CSL ducktail mold for E92, E90, and maybe E93 if we can find enough madlad 'Vert owners out in the world. 


Making us of DHL connections I established in Europe, the trunk was imported into Canada for 300$ US in 3-4 weeks. The trunk arrived on September 25th '23 and I picked it up at the local post office. 

The box arrived unharmed - for clarity this was the one of the fender's box, but it's very similar in dimensions. 

I briefly filmed and edited a trailer for the unboxing of the trunk and fenders here.  




The first immediate impressions you'll feel are its lightweight. This trunk is incredibly light, coming in at 3.5 kg / 7.7 lbs. For comparison, the OEM trunk weighs 13.4 kg / 29.5 lbs and is made of metal. 

I am not a leftie, and I don't train as much as I should - still, holding up this trunk with my arm fully extended wasn't a problem. 

Purposeful carbon use. 

This is where a signature design philosophy of Sascha shows up: he is a contract composite manufacturer for OEM race teams in Germany. His natural instincts are to perceive carbon as a first and foremost a technically superior composite for the type of products he creates.

The weight figures are explained by the complete vacuum infused carbon construction. 

My E46 M3 CSL carbon trunk by Karbonius actually had an emphasis of showing off the interior carbon work in 4x4 weave. The inner carbon sections are painted black for aesthetics. 

The outer shell's underside carbon work peaks through the painted inner section.

Every single component of the trunk is carbon: there is no fiberglass structure here, anywhere. 

Anyone that wants to insinuate this has fiberglass in any of its components is going to get roasted by yours truly. 

The outer shell is painted in an off white color, ready for paint. 

You can some resin residue of the vacuum infusion process here. None that will matter towards fitment or structural integrity of the trunk. 

This trunk uses 2x2 weave pattern on most parts as it easily conforms to complex curvatures. It's the case here once more.

The unexposed carbon work is fine - but not flawless, further reminding us of their philosophy. 

OEM fitment* > all. 

Sascha makes it a point to recreate parts to OEM levels - the CSL bumper was an exact replica, and both fender kits re-use the OEM mounting points and side grills to perfection. 

It's no different here - however, it's taken to another level of complexity on a trunk due to the intersection with the backglass, quarter panels, rear bumper, lights, locks, emblems and inner components making up the fully assembly trunk. This is where I've had issues with every other trunk I've seen.

The first thing I looked for were the trunk's edges. They are slightly rounded like OEM, unlike the grossly finished corners on my previous CSL trunk. 

The light weight of the trunk isn't achieved by cutting corners on structural integrity and material use.

You can see the thickness of the trunk here, and how sections were seamlessly bonded together and finished it off.  

How inner lights fit dictates how the trunk to quarter panel gap will loop. This is looking promising. 

The mold is 1:1 replica and was designed with the integrated mini-spoiler.

OEM functionality*. 

Retaining all OEM functionality was key for my use: the lock, lights, liner and everything else in between need to bolt in without a fuss or modifications. These features have been PITA on all my other trunks as well. 

The only missing cut out on this trunk are for the badges. However, there are small indentions showing where to punch and drill. I unfortunately couldn't catch it with the lighting at the shop. 

Update post test-fit. 

During my DIY test fit, there are actually too many cut-outs for the M3, and a few missing ones.

It was missing the wiring harness cutout for the rubber grommets, and the upper holes for the liner. This particular trunk had the keylock cutouts, I do not have it on my 2012 M3. 

The cuts are clean, with no visibly shaky hands syndrome and overcut found on other trunks. 

The same applies to the inner cut outs where the rubber adjustable mounts are threaded and the liner's push pins are clipped. I've had issues here on other trunks. 

The trunk includes threaded inserts bonded between the sections to create a structurally strong section to mount the trunk to the hinges.

This is further important on a composite trunk where things crack if they fail. 

This test trunk was also missing the holes to pop the upper liner's clips. They will be present on the production units. 

Notes on keylock. 

My 2012 M3 has comfort access and did not have a keylock mechanism on the trunk. It is however unrelated to comfort access, BMW simply removed the keylock on all E9x 3 Series starting in February 2009. 

This section is usually where the keylock mechanism bolts up. It will be optional for those who have the keylock. 

Up next: I do a DIY test fitment.

Let's see how good fitment really is.  

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