Which Milltek listing fits your BMW 1 Series?
Start with your chassis code, then your engine. For the E81 three-door, E87 five-door and E82 Coupé, Milltek lists cat-back systems for the 118d and 120d M Sport and separate ones for the 123d M Sport, each matched to its body style. The 135i Coupé and E88 Cabriolet have a secondary cat-back in two versions, one for N54-engined cars from 2008-10 and one for N55 cars from 2010-12, so check which engine your 135i has before ordering.
On the F20 and F21, the non-xDrive M135i from 2012-16 has a cat-back, rear silencers and ValveSonic+. The M140i LCI is split by its particulate filter: non-OPF cars built 2015-18 have a cat-back, ValveSonic+, HJS Tuning ECE downpipes and a large-bore downpipe, while 2019-20 cars with an OPF/GPF have their own cat-back. Smaller-engined cars are covered too, with HJS downpipes for the N13 114i, 116i, 118i and 120i (2012-15) and rear silencers for the B48 120i and 125i (2016-21). The M235i and M240i coupés are in the BMW 2 Series collection.
Filter-back exhausts for the F40 and F70 1 Series
The newer cars all carry a petrol particulate filter, so Milltek's systems fit behind it as filter-back exhausts. There are filter-back systems for the F40 M135i xDrive (2019 on) and the F40 128ti (2021 on), and a single filter-back for the F70 M135i xDrive from 2024. The F40 M135i xDrive and 128ti can also be fitted with a Maxton diffuser with a quad outlet layout. The 128ti and F70 M135i have GPF/OPF bypass pipes as well: these are louder, motorsport-oriented parts rather than road-focused upgrades.
Downpipes, valves and tips for the M135i and M140i
HJS Tuning ECE downpipes keep a catalyst in the system, which makes them the road-focused downpipe for the M140i and the N13 cars. The large-bore downpipe for the non-OPF M140i is a bigger change, and like most downpipe upgrades it will usually need an ECU remap. For downpipes and catalysts on other cars, see manifolds, de-cats and sports cats.
Several 1 Series systems come resonated or non-resonated: resonated is the quieter choice with less motorway drone, and some resonated versions are listed as EC approved. ValveSonic+ is Milltek's valved system for the M135i and M140i. Tips run from GT-80 to GT-115 in polished, Cerakote Black, titanium and burnt titanium, plus carbon fibre JET tips; compare them on the Milltek tip styles page.
Ordering your 1 Series exhaust from Milltek Exhaust Shop
With diesel, petrol, OPF and non-OPF versions in one collection, the quickest route is the reg lookup at the top of this page, which narrows the list to your car. Delivery is free in the UK, we ship worldwide, and you can pay with PayPal or Klarna. Prefer it fitted? Book your 1 Series into our Stoke-on-Trent workshop.