228i
N20

It rewrites boost, ignition and fuelling targets to lift the car from 245 bhp and 350 Nm to 280 bhp and 400 Nm, with sharper throttle mapping and a broader torque plateau. No parts are needed; the factory turbo, intercooler and exhaust all stay. In a coupé this light, the extra 50 Nm through the mid-range is immediately obvious.

Depends on budget. The M235i costs more to buy, insure and fuel; a Stage 2 228i at 320 bhp and 450 Nm closes most of the on-paper gap for far less outlay, and the four-cylinder car carries less weight over the nose. If outright pace per pound matters most, the tuned 228i is the stronger value case in the F22 range.

Yes. The ZF 8-speed automatic handles Stage 1 and Stage 2 torque on the 228i without any transmission hardware changes. If you want the gearbox to match the engine's new character, an optional TCU calibration adds quicker shifts, revised shift points and firmer lockup, but it is a refinement rather than a requirement at these power levels.

Three items: a high-flow downpipe, an upgraded intake and a larger intercooler. Together they let the standard turbo breathe well enough to hold 320 bhp and 450 Nm reliably. Fit them in any order, then send Samuel the final spec; the Stage 2 file is calibrated against what is actually on the car, not a generic parts assumption.

For most owners, no longer. Every 228i was built between 2014 and 2016, so factory warranty has expired on these cars; the practical consideration is any aftermarket or dealer-extended cover, which varies by policy. The tune itself is reversible, and the supplied stock file means the car can be returned to factory software before any inspection.