Up to 340hp for Dahler M135 Competition Line

Even with an M Dynamic Pack, the 300hp 1 Series is too plain Jane - might the Swiss be able to sort it?

By Matt Bird / Thursday, 29 January 2026 / Loading comments

The continued ordinariness of the M Performance 1 Series continues to baffle. BMW has made very successful small cars for enthusiasts before, after all. Rival manufacturers like Mercedes-AMG, Audi and Volkswagen have invested in torque vectoring rear axles to make four-wheel drive more fun (to say nothing of some very exciting powertrains). The rest of the M car catalogue right now is really very good indeed. And yet the M135 continues to plod along as a swift five-door hatchback with a nice interior - but nothing more than that. Even, it seems, with an M Dynamic Pack.

It’s well primed for some modification, then, and that’s exactly what Swiss specialists Dahler now offers with its Competition Line catalogue of upgrades for the F70 update. Power is not the main attraction here; 340hp and a stout 354lb ft is on offer from the 2.0-litre B48 turbo with an entry-level tune, and more is said to be coming if desired. Whatever the power output, though, and even with an exhaust, it’s never going to offer the thrill of a Mercedes M139 or the charm of an Audi 2.5, so it doesn’t feel like an essential upgrade.

The chassis changes are much more interesting. Now equipped with ‘built by Dahler’ coilovers that offer adjustable damping as well as ride height, ‘further sharpening of the driving dynamics’ is promised. Whether that’s helped or hindered by 20-inch wheels isn’t exactly clear; we’d err towards the latter given they’re mentioned ‘for visual refinement’. Those after the meaner look with just the wheels can opt for lowering springs paired with the factory adaptive dampers. But the coilovers on standard wheels (or even something lighter and smaller; you ain’t buying an M135 for looks) could be really good.

There isn’t a price for the suspension yet, though Dahler asks £1,221.80 plus tax for the app-controlled performance tune, so M Performance modifying is going to take some budget. That being said, M135s with just 5,000 miles are already £13k off list, so that opens up quite a potential kitty. There has to be a fun car in there somewhere - doesn’t there?