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Renntech SEC V12 Widebody: The Mercedes that Stuttgart never dared building
11/02/2026
Sometimes a tuner has to do what the factory never dared to attempt.
What if the classic Mercedes‑Benz SEC, built between 1979 and 1991, was not just an elegant S‑Class coupé, but a brutal V12 grand tourer with wide‑body ambitions? That is exactly the question Renntech asked itself. The answer is a limited run of 12 fully reengineered SECs, powered by a naturally aspirated 7.5‑liter V12 and paired with a manual transaxle.
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The engine that powered legends
Under the bonnet sits the iconic Mercedes‑Benz M120. A name that immediately resonates with those in the know. This is the powerplant that also powered the Pagani Zonda and the Mercedes‑Benz CLK GTR. Renntech enlarged displacement to 7.5 liters, retained the naturally aspirated layout, and extracted 660 hp and 650 lb‑ft of torque.
No turbos. No hybrid tricks. Just displacement, mechanical perfection, and equal‑length headers that make the V12 sound exactly as it should: deep, linear, and addictive.
Equally unique is the transmission: a bespoke manual transaxle. In an era dominated by dual‑clutch gearboxes and paddle shifters, Renntech deliberately chose pure interaction. That alone makes this restomod exceptional.
Frame‑up restoration, taken to the next level
Each SEC undergoes a complete frame‑up restoration. This is not a cosmetic refresh, but a full rebuild using modern technology. Carbon‑ceramic brakes provide stopping power to match the output, hidden behind forged two‑piece wheels. And then there is the widebody.
The widened wheel arches are not purely aesthetic. They improve aerodynamics, cooling, and high‑speed stability. The result is a C126 that looks wider, lower, and more aggressive, without losing its original elegance. This is not a shouty body kit, but a design that feels as if it always should have existed.
A V12 the factory never offered
A notable detail: Mercedes never built the SEC with a V12. During its production run, the coupé was offered with five‑ and six‑cylinder engines, as well as various V8s, but the twelve‑cylinder arrived only later with the W140 S‑Class. With this project, Renntech writes an alternative history. A what‑if scenario that has now become reality.
That makes the SEC 12 Widebody more than a restomod. It is a reinterpretation of an era when luxury, over‑engineering, and design still moved in perfect alignment.
Delivery and exclusivity
Renntech will build just 12 examples, each tailored to the individual client. First deliveries are scheduled for late 2027. Given the combination of a V12, a manual gearbox, widebody conversion, and concours‑level restoration, it is safe to say this is anything but an ordinary build.
AutoNext conclusion
The Renntech SEC V12 Widebody is the kind of car that makes you wonder why manufacturers sometimes become too cautious. A classic Mercedes coupé, reimagined with a legendary V12 and modern performance hardware, without losing its soul.
In a world of digital screens and silent EVs, this is a mechanical statement. And honestly, we will take 7.5 liters of naturally aspirated displacement over another software update any day.
