M135i/M235i tuning
Litchfield Logo
Litchfield Logo

M135i & M235i Tuning

We took delivery of one of the first M235i's in the country and since then we've been consistenly amazed by it's performance and handling. The 3 litre, 6 cylinder turbocharged engine offers a 0-60 time of 4.8 seconds, providing the perfect platform for further development.


We have created a definitive range of upgrades which will be focused on engine/power, brakes and handling and a few cosmetics tweaks.



M135i/M235i nurburgring 1
M135i/M235i nurburgring 2

Litchfield Stage 1 ECU remap - 385bhp



Our Stage 1 upgrade for the M135i/M235i turbo charged engines offers a significant increase in power and torque through its carefully re-calibrated ECU. This customised ECU mapping was developed over many months of testing on our own development vehicle to insure we are able to provide the very best calibration rather than using a generic off the shelf file. Programming of the ECU can be completed through the On Board Diagnostic (OBD) port so more time can be spent on honing the calibration. It also means we can revert the car back to standard at any time by uploading the original file.

£500.00 ex VAT


Litchfield Stage 2 upgrade - 415bhp



For those customers looking for a more complete solution we also offer our Stage 2 upgrade which combines an improved intake, intercooler and exhaust system with our Stage 2 ECU calibration to further increase power and torque.

Our larger intercooler is able to drop the temperature of the air going into the engine bay up to 25 degrees over the original design and is easily installed with no modifications to the bodywork. Combined with a less restrictive exhaust from Milltek, Remus or Akrapovic, we are able to increase power to 415 bhp.


Fitting is included in the price below, based on the Milltek exhaust system.



M135i intercooler

Stage 2 Ugrade

From £2,389.93 ex VAT





Milltek M135i/M235i Cat-Back - RACE



M135i/M235i Milltek 1
M135i/M235i Milltek 2
M135i/M235i Milltek 3
M135i/M235i Milltek 4
M135i/M235i Milltek 5


The Milltek Sport stainless steel Race exhaust system for the BMW M235i coupé includes Milltek's Active Valve technology. Titanium and Cerakote tips are available on request.


Based on the shared platform of the 1-series, Milltek Sport’s R&D team was able to carry over much of the development work it did during 2014 on the M135i model. Therefore, the new M235i Race System uses the existing and well-proven EC-approved cat back system from the M135i, but with the added feature of the outlet pipe that includes Milltek’s latest Active Valve technology, utilising OE-spec BMW electronic valves in its construction.


These intelligent new valves have been designed to seamlessly integrate with the car’s central electronics, enabling a more sporty and aggressive tone when either “Sport” or “Sport Plus” modes are selected, but when the vehicle is left in “Comfort” or “Eco Pro” modes, a more subtle and OEM-style note is produced, making for sophisticated and refined cruising comfort, even at high speed.


Consists of:


  • 1 x Flexible Connecting Pipe
  • 1 x Centre Connecting Pipe
  • 1 x Rear Silencer Assembly (Race)
  • 1 x Rear Silencer Connecting Pipe
  • 1 x Outlet Pipe
  • 1 x Outlet Pipe (with Electronic Valve Base) {Requires the electric valve motor from the OEM BMW system}
  • 2 x Polished Tip Assembly - Twin 90mm GT90
  • Pipe Ø: 3.00" (76.20mm) *

* Pipe sizes may vary from part-to-part. Pipe diameters are indicative of the system as a whole and do not necessarily mean every part is of a uniform size.

£982.46 ex VAT




Milltek M135i/M235i Cat-Back - ROAD



M135i/M235i Milltek road 1
M135i/M235i Milltek road 2
M135i/M235i Milltek road 3
M135i/M235i Milltek road 4
M135i/M235i Milltek road 5


Premium performance exhaust manufacturer Milltek Sport has released its hand-finished stainless steel exhaust system for the BMW M235i coupé. Titanium and Cerakote tips are available on request.


Based on the shared platform of the 1-series, Milltek Sport’s R&D team was able to carry over much of the development work it did during 2014 on the M135i model. Therefore, the new M235i system uses the existing and well-proven EC-approved cat back system from the M135i.


The Milltek Cat-Back system helps to improve throttle response whilst giving the car a more purposeful sound.


Consists of:


  • 1 x Flexible Connecting Pipe
  • 1 x Centre Connecting Pipe
  • 1 x Rear Silencer (ROAD)
  • 1 x Rear Silencer Connecting Pipe
  • 2 x Outlet Pipe
  • 2 x Polished Tip Assembly - Twin 90mm GT90
  • Pipe Ø: 3.00" (76.20mm) *

* Pipe sizes may vary from part-to-part. Pipe diameters are indicative of the system as a whole and do not necessarily mean every part is of a uniform size.

£870.39 ex VAT



remus logo

Remus M235i Cat-Back Exhaust



M135i/M235i Remus 1
M135i/M235i Remus 2
M135i/M235i Remus 3


The stainless steel cat-back exhaust system has been designed to produce an aggressive exhaust note whilst increasing throttle response. There are two tail trim options (black or silver) and two rear silencer volume options (wolf inside or wolf inside RACING).




From £1158.00 ex VAT


eibach logo

The Eibach springs and Anti-Roll bar kit are a great first step in improving the handling of the M135i/M235i.



M135i/M235i eibach pro kit

Eibach Pro-Kit



The Eibach Pro-Kit springs help to reduce squat under acceleration by lowering the car's centre of gravity whilst giving a more aggressive look. This kit lowers the M235i by around 20mm at the front, 10mm at the rear.

£195.60 ex VAT


M135i/M235i anti-roll bar

Eibach Anti-Roll Bar Kit



The Eibach Anti-Roll bar kit help to keep body-roll at a minimum by controlling lateral and centrifugal forces. The result is improved handling and increased grip whilst cornering.

£313.33 ex VAT


M135i/M235i Eibach spacers

Eibach 10mm Pro-Spacers



The Eibach wheel spacers help to improve the look of your M235i by increasing the track width, filling the arches better. The 10mm Eibach spacers come as a pair, increasing the overall track width by 20mm.

£89.95 ex VAT


bilstein logo
M135i/M235i Bilstein B16

Bilstein B16 PSS10 Ride Control Suspension



For the next level of handling upgrade we would recommend the B16 Ridecontrol. It's aimed at those drivers who want a faster road setup but who also venture on to the track from time to time. Drivers can simply switch between 'Comfort' and 'Sport' modes at the push of a button.


  • Sport mode for excellent driving dynamics and maximum power reserves in all situations
  • Comfort mode creates smooth compensation for uneven surfaces
  • Illuminated operator button for controlling settings
  • Threaded body adjustable range of 20 mm at both axles, while installed
  • Lowering of approx. 30-50 mm at front and rear
  • Road-tested by BILSTEIN under motor sports conditions and fine-tuned
  • Surface coating using Triple-C-Technology for long-lasting corrosion resistance
  • Quality sport springs made from highly durable material
  • BILSTEIN mono-tube/Upside-Down technology, made in Germany
  • German TÜV certificate

£1,740.87 ex VAT




Quaife diff

Quaife diff 2

M135i/M235i Quaife Differential Upgrade



The Exchange Quaife BMW Final Drive is a direct replacement for the standard 1 Series (F20/F21) M135i and M235i.


The Quaife ATB Helical LSD differential transforms your cars performance by substantially reducing or eliminating wheelspin, preventing the onset of traction control intervention, thus maintaining full engine power and acceleration on demand.


Unlike a conventional limited slip differential, the Quaife ATB Helical LSD differential relies on gears rather than clutch plates for its operation. That means it is much smoother in operation, and does not cause any interference with the standard traction and stability control electronics. The Quaife ATB Helical LSD differential never locks harshly with a set pre-load of wheel slip across the driven axle, like a conventional clutched LSD. Rather, the M135i Manual Quaife ATB Helical LSD differential automatically biases the torque away from the spinning wheel across the axle, to a constantly varying degree, and never locks.


Quaife ATB Helical LSD differentials have many benefits over a standard open differential, including maximising traction, minimizing wheel spin. They also eliminate the torque steer and snatching compared to conventional LSD units, and are a maintenance-free design retaining the standard oil lubrication and specifications.


The Quaife ATB Helical LSD differential is proven in circuit and drag racing, rallying and road use, is produced from Corus steel billets, and is CAD designed, CNC machined, then inspected to the rigorous ISO 9001 standard. With over 1,250 different applications, the Quaife ATB Helical LSD differential is second to none. Accept no imitations! Quaife ATB Helical LSD differentials are used by Ford, General Motors and Daimler-Chrysler as original equipment.


£1,588.88 ex VAT

£1,906.66 inc VAT