Hot hatch made hotter! This used to be a BMW M135i xDrive with the N55 engine, but the owner decided to spice things up. Underneath the hood is now an S55 borrowed from an F80 M3, bringing a substantial jump in power. The original engine had 315 hp whereas its replacement packs 425 hp. Torque is also way up, jumping by 100 Nm (74 lb-ft) to 550 Nm (406 lb-ft).

We get to see the three-door hatch (F21) being pushed to the maximum in Germany on an unrestricted section of the Autobahn. Eagle-eyed readers will notice the aftermarket digital instrument cluster inside an otherwise stock cabin from an era when BMW interiors had plenty of buttons. Despite the engine transplant and custom quad exhaust, the car doesn’t sound particularly exciting, but it sure is quick.

This M135i comes from a golden period in time when BMW was making the 1 Series on a rear-wheel-drive platform. Today’s car is built on an FWD architecture, and it’ll be the same story with the next-generation model coming later in 2024. Back in the day, the German luxury brand was selling the M135i with standard RWD and optional xDrive whereas nowadays it’s an AWD-only affair.

This amped-up M135i isn’t the most hardcore build we’ve seen since other enthusiasts have done V8 swaps. Nevertheless, it’s a rapid Autobahn missile, although we’re left wondering why it still has a top speed limiter. A manual gearbox would’ve made it even better, and we would’ve honestly kept the original analog dials.

The F20/F21 1 Series wasn’t the prettiest car BMW in the 2010s but the LCI did improve things here and there. The cabin has aged gracefully, which we’re not sure we’ll be able to say about current interiors with supersized screens. Seeing the glass half full, at least we’re getting another M135i xDrive.

Source: AutoTopNL / YouTube