Best First Mods for Your G80 M3 / G82 M4
Just picked up a G80 M3 or G82 M4? Congrats — the S58 is one of the best engines BMW has ever built. Here's how to get the most out of it without wasting money on the wrong mods.
The S58 Stock Baseline
- 473 HP (standard) / 503 HP (Competition)
- Twin turbo inline-6
- 0–60 in ~3.4 seconds (Comp, xDrive)
This is already a seriously fast car. The goal with modding isn't to fix something broken — it's to unlock what BMW left on the table.
Mod Order — Do This First
1. MHD Flash Tune + Wireless Adapter (~$450 total)
Gain: +70–80 WHP
Single biggest bang-for-buck mod on ANY modern BMW. A Stage 1 tune on the S58 puts you around 570 WHP with zero other modifications. That's supercar territory from a software change.
You'll need:
- MHD Wireless WiFi Adapter — $79
- MHD Super License — $375
- 2021+ models: FEMTO ECU Unlock first (required before any tuning)
2. Upgraded Spark Plugs (~$80)
Gain: Reliability insurance
Not a power mod — a reliability mod. Once you're tuned and making 570+ WHP, you want colder plugs to prevent pre-detonation. Replace every 15K miles when tuned.
3. RKTunes S58 Front Mount Intakes (~$700)
Gain: +20–30 WHP on top of tune, better sound
Our S58 front mount intakes replace the stock airboxes with high-flow units behind the kidney grills. You'll hear the turbos spool, feel more responsive throttle, and pick up real power. Available in multiple color combos.
4. Oil Cooler Guard
Gain: Peace of mind
The S58's oil cooler sits exposed behind the front bumper with zero protection. One rock at highway speed can puncture it. Cheap insurance against a $5,000+ repair.
What NOT to Do First
- Don't start with an exhaust. Sounds amazing but adds minimal power on a turbo car.
- Don't buy a JB4 if you plan to eventually flash tune. MHD is a more complete solution.
- Don't ignore the ECU unlock on 2021+ cars. No unlock = no tune = wasted money.
Questions? Contact us or DM us on Instagram @rktunes.