"Stage 1" and "Stage 2" get used a lot, and they don't mean exactly the same thing at every tuner. This guide explains what the stages usually mean on BMW's B58 (M340i, M240i, X3 M40i, Toyota GR Supra) and S58 (G80 M3, G82 M4, G87 M2, X3 M/X4 M), and which supporting parts go with each one.
Stage 1: tune only
A Stage 1 tune changes boost, fuelling and timing on a stock car. There's no hardware change, and it's the best value gain on both engines. Common platforms are Bootmod3 and MHD.
- Good to have: a quality intake and upgraded charge pipes. The factory plastic charge pipes on the B58 are a known weak point once boost goes up.
Stage 2: downpipes + tune
Stage 2 adds less restrictive downpipes and a tune written for them. It improves turbo spool and top-end power, and makes the car noticeably louder.
- Catted vs catless: catted (for example 200-cell) downpipes keep a catalytic converter in the system. Catless downpipes are for off-road and competition use only. Ask us which option suits how you use the car.
- Tune is required: fitting downpipes without the matching tune will usually trigger engine lights.
Beyond Stage 2
Past Stage 2, the limit is usually heat and fuel rather than airflow:
- Cooling: upgraded heat exchangers, charge coolers or a chiller system keep intake temperatures consistent, especially in Australian summer and on track.
- Fuel: ethanol blends (E30 and up) or port injection. The S58 intake manifold with port injection is one example.
- Midpipes and exhaust: on the S58, midpipes and valved cat-backs change the sound more than the power. See our S58 downpipes vs midpipes guide.
B58 vs S58: the short version
- B58: single turbo with a lot of headroom. Charge pipes, a good tune and cooling go a long way.
- S58: twin turbo from the factory M cars. Downpipes and a tune are the big step; cooling matters for repeat track laps.
Planning your build in Adelaide
SL Autowerkes confirms fitment, tune compatibility and freight before anything is ordered, and can supply only or supply and fit at our Stepney workshop. Browse BMW parts or get in touch with your car's details.