"In this final entry to the Series, we finalize the little things that matter to achieve an OEM level conversion. I document the installation of the headliner & rear shelf prior to refitting the front and rear windows, along with all accessories.

I wrap it up with detailed numbers, and my closing thoughts on the benefits of the conversion."
- Matt

The final stretch. 

This entry documents the final re-assembly of the M5's carbon roof conversion in December '24, nearly 12 months removed from the inception of the project. At this stage, we had 99% of all components on hand to finalize the installation. 

The installation has multiple while-you're-in-there that are useful to cover. In the previous entry, I focused on the restoration process of the Alcantara rear shelf. They are not required for a successful installation, but they come highly recommended to limit future downtime, costs and [...] have a near brand new M5. 

The adhesives cured for multiple days as the final parts came in from BMW. 

The two insulation pads are adhesives backed. They were fitted directly to the underside of the carbon panel.

They essentially cover the entire panel, providing what should be superior insulation compared to the sunroof cassette. 

3x new sound absorbers from BMW were fitted to the rear of the carbon roof like the original metal sunroof panel. It's unclear whether those were required for the slicktop. Sound insulation and absorption are two different methods of sound deadening. we opted to use both.  

The rear pad has cut outs made to fit with the slicktop's design.  

The insulation pads leave little to no exposed areas, confirming to the roof bar. 

It also features a rear cut out for the antenna, allowing access to fit and connect the antenna. 

Prior to fitting the windows and headliner, I proceeded with fitting the restored rear shelf. 

The rear shelf is positioned easily. The shelf fits underneath the rear plastic trim, and the 3x middle section cutouts align it. 

The trims for the rear sunshade corners were clipped in. They ensure the sunshade fits snugly to the shelf. 

The corner trims of the rear are clipped into the chassis using push pins. 

The plastic trim behind the folding seats was aligned and clipped in. 

The corner holes of the seat belt trim and folding seat trim overlap to dictate the alignment of the rear shelf. They are clipped together into the chassis with a push pin.

There are additional push pins across the upper section of the trim. 

The tweeters and speakers are bolted into the rear shelf using the g-clips. It's a good to clean the speakers, removing any dust or debris that can cause sound distortions.

A source of these distortions can be the deteriorating foams glued on the underside of the speaker covers. Ideally, these would be replaced. 

Done! The rear shelf was fully bolted in. This must be done before you put in the C pillar covers. 

Next: the headliner was slid into from the rear. It is much bigger than the E46s and required 2x sets of hands to properly align, and avoid damaging it in the process. 

The headliner is first bolted to the roof and chassis by sandwiching it with the grab handles. 

Afterwards, the sun visors are bolted to the front transversal bar to further solidify its position. 

We positioned the wiring harnesses across the headliner progressively as to avoid bending the headliner and creating wrinkles in the Alcantara. They could be ironed out later on if it happened. 

The wiring for the former sunroof was plugged away, while we retained the SOS phone and passenger airbag indicator. We had not yet received the new cover at this time. It was the only missing BMW part to fully complete the headliner. 

The headliner's fitment was to OEM level across all gaps with A, B and C pillars, along with color matching with the original Alcantara. You may have to adjust the lower B pillar and door trim upwards if a gap is create by the B pillars. 

Glasses & Gaskets.

With the headliner fully bolted in, it was time for the last major component of the installation: fitting the windshield and rear glass, along with all its electronic accessories. 

The E60 M5 has a myriad of electronic components that depend on the proper installation of these windows. Notably, my E60 was spec'ed with the Heads Up Display (HUD). 

Although it's an old, gameboy'esque interface, I like it!

My previous windshield was old and pitted from Winter use: it already had 2x spot repairs performed. It fortunately cracked upon removal and forced a replacement.  

The part numbers for aftermarket glasses didn't match, and it was unclear it they would properly display information. Some have had luck combining after glass with ceramic tint for displaying HUD.

Considering the risks and our timeline, I chose to replace the windshield with a brand new Genuine BMW unit to ensure its proper functioning. 

I do not source glass for this conversion due to shipping risks. I highly recommend you source it locally, and put the liability for delivery on your BMW dealership.  

While in there, I replaced all gaskets. The E60's windshield is designed with a single upper gasket. In high UV environments, this tends to degrade and crack. Mine hadn't but was still visually worn. 

The windshield was professionally installed. It seals with the chassis using urethane. 

Properly applied urethane forms a uniform seal across the sealing surface. 

Fitting the windshield required 2x sets of hands. The urethane allows some adjustment to ensure it sits and aligned correctly with all gaps. 

The E60 uses molding trims on the side of the windshield for aesthetic and functional purposes as it guides water down the drains. I highly recommend you source new molding clips as they tend to easily break. They're cheap and ensure a tight seal. 

The rear view mirror was installed, its covers clipped in and connectors plugged into the harness. 

While in there, we also replaced the windshield cowl. The black plastic tends to fade and the rubber seal tends to decay from the elements. It's an inexpensive part and I highly recommend it. 

As it wasn't damaged nor worn, we chose to re-use the original rear window. It features more electronic components than the windshield. The 3rd brake light, another antenna, and heating elements are all directly on the window. 

The 3rd brake light and its cover were clipped directly to the window prior to installation. 

This trim is actually your antenna trim. You must be careful to avoid damaging it as it will cause door locking and unlocking problems. 

This is the antenna itself. The board needs to be precisely clipped into the antenna trim. It makes contact with the window in specific locations to ensure proper signal reception.  The board has fiber optic connectors by the roof antenna that also need to be connected. 

The rear window has 2x gaskets. One covers the upper and side sections of the window. The lower gasket is not pictured here and was installed subsequently. It seals the window with the trunk. I highly recommend you replace both. 

Bam! 

The roof panel, antenna and gasket harmoniously aligned: subtle signs of a proper factory-like carbon roof installation. 

Misc loose ends.

I unfortunately missed the remaining final steps of the installation. Holidays were arriving rapidly and I was focused on the BlackFriday campaigns.

During my absence, the roof rails, A and C pillars, windshield wipers and other accessories were fitted later on as part of broader repair and restoration work. While-in-there, we installed new door sills, front door seals and resprayed the windshield moldings before completion.

We installed the roof rails without the original roof rail clips. They act as spacers to align the with the roof panel. It's most prevalent for the front window. 

I will come back to this entry later on and update it with further details on installing the roof rails, and the headliner cover that we are awaiting from BMW. 

The car was driven for a few weeks. With the paint cured and settled, the front clip and roof panel were covered with Paint Protection Film (PPF). The recent restoration marked the end of any Winter use for the M5 V10. It is stored until Spring comes. 

Closing thoughts.

In traditional fashion for the E60 M5, the development of the carbon roof conversion has been a roller coaster of high and lows, with little time to take a breather.

The Series stretches from the initial purchase of the original slicktop metal roof panel in early '2024 to the final rollout in December '24. The process was inevitably delayed by the fender bender in September '24, leading to prolonged delays in sourcing parts and completing work.

I wrote the entries to the installation process in January '25, taking a few weeks to reflect upon the process.

This all inevitably begs the question: was it worth it? Let's crunch the utilitarian numbers first, and put them into perspective.

The numbers. 

With numbers crushed, the pain is revealed: the carbon roof conversion for the E60 M5 sits amongst the highest $ per lbs/kg of any weight reduction project you could take on. 

The inevitable M6 arguments lays its claim here: there's a lighter, cheaper V10 experience with an original carbon roof readily available. It's the more rational choice.

A new option for weight reduction. 

Nonetheless, the carbon roof conversion adds a component to the usual weight reduction upgrades: lighter exhaust systems, wheels & brakes, lithium batteries and and carbon bucket seats. 

A pathway to a 3,7xx lbs E60 M5 with complete interior now exists. For comparaison, the original E90 M3 DCT weights 3,7xx lbs depending on options. 

Additional tangible benefits.  

Beyond weight reduction, the carbon roof conversion presents further tangible benefits compared to the original metal roof. The improved sound insulation reduces wind noises and the slick top roof eliminates light leaks into the cabin by the sunroof panel.

Evidently, the removal of the sunroof cassette eliminate reliability risks related to infiltration risks and wearing gaskets. Truth be told, the tangible benefits weren't on my mind to begin with. 

As with most things M5 V10, it's the intangibles that make it a must-have.

I was driven by one core goal: taking another step towards the re-creation of the prototype M5 CSL.

This was the only justification I needed.