BMW’s hot hatch formula has always walked a fine line between daily usability and the ability to set a decent time at the Nürburgring. With the fourth-generation BMW M135 (F70), that balance is sharper than ever. And now, dAHLer Competition Line has stepped in to turn the dial a few clicks further into “seriously quick”.
This is not a wild one-off show build. It’s a full, homologated upgrade programme designed to make BMW’s premium hot hatch faster, louder, lower, and meaner, without upsetting the daily commute or your local emissions inspector.
What Has dAHLer Changed On The BMW M135?
dAHLer has developed a comprehensive Competition Line package that covers power, chassis, exhaust, and visuals. The headline upgrade is Stage 1 “powered by dAHLer”. It boosts the 2.0-litre B48 turbo from 300hp to 340 hp, while torque jumps from 400Nm to a chunky 480Nm. For a hot hatch that weighs just over 1,500 kilos, the performance gains are pretty significant.
What’s Your Pick?
BMW M135 dAHLer
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Is The Power Upgrade Road-Legal & Daily Usable?
Yes, and that’s the key point. The Stage 1 upgrade complies with Euro 6e standards under WLTP and comes with EU and Swiss homologation. You can run the power upgrade, the exhaust, or both together without triggering legal headaches.
There is also a Stage 2 option for those who feel Stage 1 is merely “adequate”, though dAHLer keeps the details understated. Swiss tuning is about restraint, not shouting numbers on Instagram.
Is The Exhaust System Upgraded On The dAHLer BMW M135?
dAHLer offers a stainless-steel, four-pipe complete exhaust system built in-house. Visually, it fills the rear end exactly as an M Performance hatch should. Acoustically, expect a deeper, more purposeful tone rather than anti-social crackle theatrics.
How Has dAHLer improved The Handling?
For drivers who actually care about cornering, dAHLer’s high-performance coilover suspension allows adjustable lowering and configurable damping stiffness. You can tailor it for smooth autobahns, mountain passes, or your favourite empty roundabout at 2am.
If you prefer something simpler, sport springs are available, matched specifically to the factory adaptive M suspension. Less adjustability, but still a noticeably sharper stance and response.
Does The Visual Upgrade Match The Performance Gains?
Absolutely. dAHLer’s in-house CDC wheels do most of the talking. The CDC1 features a bold ten-spoke design, while the CDC2 Forged plays with layered double-spoke geometry for a strong three-dimensional look.
Both are offered in 20-inch sizes with 235-section tyres and multiple finishes available. There’s even a CDC2 “dAHLer Edition” with partially polished faces for maximum visual drama. A carbon front spoiler lip is also in development.
Is This The Ultimate BMW M135 Build?
For a road-focused hot hatch, it’s hard to argue otherwise. The dAHLer Competition Line doesn’t try to reinvent the M135 but simply refines everything BMW already did right, then adds performance and soul. It’s the kind of upgrade package that feels OEM+, just angrier. And honestly, that’s exactly how a modern BMW hot hatch should be.
