STX Tuning
WhatsApp STX TuningCall STX Tuning

BMW M850i xDrive G14/G15/G16 ECU Remapping

BMW M850i xDrive G14/G15/G164.4 N63 V8 · 2018–Present

Stage 1 £599

Get my quote →
4.9/5500+ Google ReviewsSee Google Reviews

The BMW M850i xDrive G14/G15/G16 (2018 to Present) leaves the factory with 530 PS and 750 Nm from its 4.4 petrol engine. Our Stage 1 estimate takes it to 650 PS and 850 Nm, roughly 23% more power and 13% more torque.

Stage 1 price

£599

Stage 1 ECU remap

Estimated gain

+120 PS · +100 Nm

Power

Stock
530 PS
Stage 1
650 PS

Torque

Stock
750 Nm
Stage 1
850 Nm

Figures are STX Tuning estimates for a healthy standard car, not a dyno result for your vehicle. Power is shown in PS. These are existing vehicle library estimates, not independently measured results.

Where would you like it done?
01753 439130
WhatsApp STX Tuning

More BMW tuning

1 Series F20/F21

118i 1.6 Petrol

135i E82/E88

135i 3.0 Petrol

1M Coupe E82

1M Coupe 3.0 Petrol

3 Series G20/G21

320d 2.0 Diesel

3 Series F30/F31

320d 2.0 Diesel

3 Series F30/F31

330i 2.0 Petrol

330d E90/E91/E92

330d 3.0 Diesel

330d F30/F31

330d 3.0 Diesel

What we do

More than just ECU remapping.

From Stage 1 and Stage 2 ECU remapping to gearbox tuning and supporting performance upgrades, STX Tuning offers specialist vehicle software and tuning services for compatible petrol and diesel cars and vans.

Explore the available options for your exact vehicle at our Slough workshop, with suitable mobile ECU remapping appointments available across selected surrounding areas.

Not sure which tuning service you need?

Tell us what you drive and what you'd like to achieve. We'll check your vehicle and help you explore the available options.

4.9/5 | 500+ Google Reviews
Get my tuning quoteCall STX Tuning: 01753 439130

Get Your M850i xDrive G14/G15/G16 Quote

Select one or more services and send your enquiry to STX Tuning.

Your vehicle
What do you need?

1 service selected: Stage 1

Where would you prefer the work?
Your details

We save your enquiry first, then WhatsApp opens with your message ready. Press Send in WhatsApp to complete it.

Call STX: 01753 439130
  • 4.9/5 Google rating · 535 reviews
  • Slough workshop
  • Vehicle-specific quotes

No payment needed. We use your details only to handle this enquiry. See our privacy policy.

Google Customer Reviews

What BMW Owners Say

See what customers say about their experience with STX Tuning.

Google Reviews

4.9

535 Google Reviews

  • Tiinkerj

    Jul 2026

    I wanted to leave a genuine review, I got my car remapped on the 5th June 2026. Making the appointment was very easy, I didn’t have to wait too long for an appointment and had the option for someone to come to my house if needed. The remap was done within an hour or so. My light did come back on a week after the remap was done, but I was able to clear it with no issues and last weekend I took a 4 hour round trip to the beach and the light did not come back on when usually it does after about 1hr into a drive. The point of my long review is I highly recommend this company and I am very happy with the service provided.

    Posted on Google · view on our Google profile

  • Oscar Rapala

    Jun 2026

    First time tuning my car. Didn’t know what to expect but it was amazing. They explained everything to me clearly, how it works etc and before you know it my car was ready. 10/10 polite service. Will be coming back in the future with serious motors, can tell these guys are professionals judging by tons of performance cars outside.

    Posted on Google · view on our Google profile

  • Jamiah Woodroffe

    Apr 2026

    Really five star service I’ve only got my car the day before I messaged on a Sunday just as an inquiry was more than Happy to take time of the day on a Sunday to fit me in last minute just want to think the whole team very professional and I absolutely love my car. I felt an instant power boost and explained everything to me and packages that I can definitely most likely in the future upgrade to will be definitely coming again.

    Posted on Google · view on our Google profile

  • Tracy

    Jan 2026

    Amazing company, arrived within 2 hours of my call and fixed the problem where another garage had failed. So happy to have the issue resolved, technician was so nice and explained everything, excellent service, highly recommend STX Tuning

    Posted on Google · view on our Google profile

  • Jake Bickmore

    Dec 2025

    STX Tuning were absolutely brilliant. The service was super fast — same day turnaround — and they solved an issue with my car that a main dealer claimed would cost me thousands to fix. It turned out the expensive repair wasn’t even necessary, and STX handled it quickly and professionally. Honest, efficient, and highly recommended!

    Posted on Google · view on our Google profile
Read all Google reviews Ask STX on WhatsApp