Best BMW M240i Exhaust Systems: F22 & G42 Buyer Guide

The best BMW M240i exhaust upgrade wakes up one of the most underrated engines BMW builds — the turbocharged 3.0-liter inline-six. In the current G42 M240i (2022 and up) that B58 makes 382 hp and 369 lb-ft, launching the coupe to 60 mph in a BMW-quoted 4.1 seconds (independent tests have hit 3.6). The earlier F22/F23 M240i (2016–2021) uses the same-family N55 and B58 sixes rated at 335 hp. All of them ship from the factory with a muted, GPF-choked note that hides the engine's character. A well-chosen cat-back, slip-on, or axle-back fixes that. This guide compares five in-stock BMW M240i exhaust systems — from a $699.99 MBRP to a $7,036.89 Akrapovic titanium slip-on — with real specs, fitment, and sound notes so you can match the right kit to your exact car.

Why upgrade the BMW M240i exhaust?

A BMW M240i exhaust upgrade unlocks sound, saves weight, and can add a small amount of power on an otherwise very quiet platform. From the factory the M240i runs a restrictive rear muffler and, on 2019-and-later cars, a gasoline particulate filter (GPF/OPF) that mutes the B58's naturally aggressive tone. Swapping the rear section — whether an axle-back, slip-on, or full cat-back — is the single most effective way to hear the turbo six.

The gains are three-fold. First, sound: the M240i goes from luxury-quiet to a deep straight-six growl with pops on overrun. Second, weight: titanium systems like the Akrapovic drop 4.0 kg (8.8 lb) versus the steel factory unit, all of it behind the rear axle. Third, power: on a stock tune the rear-only change is modest — Akrapovic measured +9.7 hp and +15.1 lb-ft at 2,450 rpm on its own dyno — but it frees the exhaust for bigger gains once you add a tune and downpipe later.

Best BMW M240i exhaust systems at a glance

Here are the five best BMW M240i exhaust systems we stock, compared side by side. The Akrapovic is the only option engineered for the current G42 chassis (2022+); the Remus, AWE, and MBRP kits fit the F22/F23 M240i and M235i (2014–2021). Confirm your chassis before buying — the two generations do not share exhaust hardware.

1. Akrapovic Slip-On Line (Titanium) — Best G42 M240i Exhaust

The Akrapovic Slip-On Line (Titanium) is the best exhaust for the 2022–2026 G42 BMW M240i and M440i. It is the only rear-section system on this list engineered specifically for the current chassis, and it is built entirely from lightweight high-grade titanium with hand-crafted carbon-fiber tailpipes. Akrapovic quotes a 4.0 kg (8.8 lb) weight saving over the factory exhaust and a dyno-verified gain of 9.7 hp and 20.5 Nm (15.1 lb-ft) at 2,450 rpm on a stock car.

Where a factory G42 exhaust has a single valve, the Akrapovic runs two — one per side of the central muffler — plus a pair of resonators to keep the tone smooth at cruise and open it into a deep, sporty roar under load. A TNG (Take-and-Go) valve controller is included, and installation requires one extra factory valve actuator (BMW part 18 30 8 686 640). Because the system carries ECE type approval, no remapping is needed on OPF-equipped cars — you keep your warranty-friendly tune and emissions compliance.

2. Remus Axle-Back with Front Section — Best F22 M240i Sound

The Remus axle-back with front section and carbon tail pipes is the most complete rear-exhaust upgrade for the 2016–2021 F22/F23 M240i. By replacing both the mid and rear sections in 304 stainless steel, this German-engineered system delivers the biggest sound change of any F22 kit here while keeping fitment plug-and-play. At $2,486.35 it sits between the budget axle-backs and the Akrapovic, and the carbon tips add a motorsport look to the rear valance.

3. Remus Axle-Back (non-GPF) — Best Valved Value

The Remus non-GPF axle-back is the smart-money choice for 2016–2018 F22 M240i owners whose cars were built before the gasoline particulate filter. At $1,715.34 it brings the same Remus 304-stainless build and carbon tips as the flagship kit, minus the front section, for a cleaner, louder note without the full-system cost. Because it is designed for pre-GPF cars, always confirm your build date before ordering.

4. AWE Touring Edition Axle-Back — Best Drone-Free Daily

The AWE Tuning Touring Edition axle-back is the best drone-free BMW M240i exhaust for daily drivers. AWE tunes its Touring systems with 180 Technology to cancel the resonant frequencies that cause cabin drone, so you get a richer straight-six note at wide-open throttle without the highway headache. This kit fits F22 M235i and M240i (2014–2021), costs $1,485.00, and ships with 102mm Diamond Black tips for a stealthy finish.

5. MBRP 3in Axle-Back (Street) — Best Budget M240i Exhaust

The MBRP 3-inch axle-back is the best budget BMW M240i exhaust at $699.99. Built from mandrel-bent T304 stainless steel with dual rear-exit carbon-fiber tips, this Street Version opens up the B58's voice for a fraction of the premium kits while keeping a manageable, drone-conscious volume. It fits 2017–2021 F22 M240i and is the easiest way to lose the factory mute for under a grand.

F22 vs G42: which BMW M240i do you have?

Your M240i chassis determines which exhaust fits. The F22/F23 M240i was sold from 2016 to 2021 and shares its rear-section hardware with the F22 M235i; the G42 M240i arrived for 2022 and uses a completely different underbody. Exhausts do not cross over between the two. A quick way to tell them apart: the F22 is the rounder, smaller coupe with the pre-2022 iDrive; the G42 is wider, has the frameless doors, and wears the current curved dashboard display.

Engine-wise, 2016 F22 M240i cars use the N55 single-turbo six (335 hp), 2017–2021 F22 cars switched to the B58 (335 hp / 369 lb-ft), and the G42 runs the uprated B58 at 382 hp / 369 lb-ft. On this list, the Akrapovic is your only G42 option; the Remus, AWE, and MBRP kits are all F22/F23.

Axle-back vs slip-on vs cat-back — what should you buy?

An axle-back replaces only the rearmost muffler section and is the simplest, cheapest way to add sound. A slip-on (Akrapovic's term) swaps the rear muffler and tips as a bolt-on unit engineered to work with the factory valve. A cat-back replaces everything from the catalytic converter rearward, including the mid-pipe, for the largest sound and flow change. For a stock or lightly tuned M240i, an axle-back or slip-on gives you 90% of the sound with the least fuss; step up to a full cat-back or add a downpipe and tune only when you are chasing serious power.

Because the M240i is turbocharged, a rear-section exhaust on a stock tune adds only small power on its own — think single-digit horsepower, as Akrapovic's 9.7 hp figure shows. The real reason to buy is the sound and weight. If power is the goal, plan to pair your exhaust with a downpipe and a B58 tune, which together can push a G42 well past 450 wheel horsepower.

Do you need a tune for an M240i exhaust?

No, you do not need a tune to run any exhaust in this guide. All five systems are rear-section (axle-back or slip-on) upgrades that bolt on and work with the factory ECU and, where applicable, the factory exhaust valve. The Akrapovic Slip-On even carries ECE type approval, so OPF-equipped G42 cars keep full emissions compliance with no remap. A tune only becomes necessary if you later add a high-flow downpipe or chase big power numbers.