Which mods should you make to your BMW M3/M4 F8x?

Which mods should you make to your BMW M3/M4 F8x?

by KITS UK on Feb 26, 2025 Categories: KITS UK - BLOG

Are you the lucky owner of the iconic BMW M3/M4 F80-F82 range? If so we will explore in this blog which mods we recommend from performance to styling. 

Engine/ Performance

Discussions on social media platforms are rife surrounding performance modifications and remapping. The F8x platform already delivers 420bhp+ for you to enjoy, however when you become comfortable with its power and characteristics, you'll likely want more! 

Stage 1 Remap

This is primarily ECU based. If you want figures on paper then we recommend enlisting the services of a reputable tuning company who can fine tune the map on a dyno which will give you accurate readings. Bear in mind that dynos differ in calibration from company to company so charts may differ.

If figures on paper do not interest you then we recommend the BootMod3 platform. Easy to install yourself using your laptop and OBD connection, you have a good selection of OTS maps to choose from. Maps can be changed to your liking and you can also monitor the platform using the BM3 app. This platform also caters for stage 2/3 as well, however we highly recommend that anything above stage 1 should be done by an experienced professional. A stage 1 tune should output approximately 549BHP, highly dependant on the map used.

Stage 2+

The first thing you should consider when venturing further than stage 1 is the commonly known crank hub fix. The F8x platform is notorious for spinning the crank hub when exposed to power beyond that of stage 1. This can be catastrophic for your S55 engine block, which naturally you need to avoid. Again, this should be the very first fix you should be looking at if you wish to progress with your quest for maximum BHP and torque.

A stage 2 usually involves the upgraded ECU map as well as...

  • 3" Decat or Sports CAT downpipes
  • Charge pipes
  • Air Filter Upgrade
  • ECU pops & bangs
  • Cold Start Noise Reduction
  • Top speed limiter removal
  • Optional xHP Transmission Software upgrade.

Typical output would be 585BHP - 730nm Torque.

Exterior Styling

Ever seen an F80/F82 driving along without the M Performance body styling kit? Awful isn't it! Here at KITS UK we give our suggestions on which exterior styling modifications we recommend.

  1. Carbon Fibre Splitter

So many options here! You have the OEM style M Performance splitter which includes the Carbon Fibre air intake ducts and lower lip. OEM costs for this modification are astronomical, usually approx £1800 for all 3 pieces. This is without fitting! Our aftermarket options are much more cost effective in the region of £399 plus fitting. This is for the wet carbon option, which naturally comes in much cheaper than the pre-preg dry carbon. Styles include...

  • MP Style
  • CS Style
  • 3D Style
  • PS Style
  • V Style

Caution must be taken when purchasing some of these option as the air intake carbon trims do not fit with all of the options so ask us or your chosen styling supplier before making your purchase.

2. Carbon Fibre Diffuser

Not as many options as the splitter, however you need to consider the look you are pursuing. 

  • MP Style (Direct replacement OEM Style. Subtle)
  • V Style 3pcs (Aggressive and "chunky". Bear in mind that a set of carbon fibre exhaust tips will be required when selecting this option otherwise your stock OEM tips will look a little lost).
  • 3D Style (a nice subtle option which will wrap around the entire lower edge of the bumper)

3. Carbon Fibre Side Skirt Extensions

We only recommend 2 options with the side extensions which cover both subtle and aggressive.

  • MP Style (subtle and OEM look, however BMW never offered these in carbon, only matte black)
  • PSM Style (large and extremely aggressive)

4. Carbon Fibre Boot Spoiler

As with the splitter options, there are many styles for the boot lid of both the M3 and the M4.

  • MP Style M3 (Subtle and OEM look, much similar to the spoiler supplied from main dealer)
  • PSM Style (Large ducktail look with a cutout in the centre)
  • CS Style (OEM look from the CS models)
  • V Style (Small option which resembles the OEM M4 spoiler. Also available for the M3)

5. Carbon Fibre Grilles

Direct replacement for the stock gloss black or chrome grilles.

6. Carbon Fibre Mirror Caps

Direct replacement for the stock colour coded mirror caps.

7. Carbon Fibre Side Vent Trims

Direct replacement for the stock chrome or gloss black side vent trims. Point to note with this product, you need to swap over your metal M3/M4 badge over to the carbon fibre trim. BMW do not sell these separately.

So as you can see above, there’s so many options available for the F8x platform. You can stay subtle or you can go “balls to the wall”, you have the choice! Here at KITS UK we supply all styling products in Carbon fibre and gloss black. We also have a professional fitting facility staffed with extremely experienced technicians who do this work all day every day, so we know the brand inside out.

Get in touch today and we will be happy to talk you through the next steps for modifying your iconic F8x!