Stage 1, 2 and 3 — what those numbers actually mean
There is no standard, and that gets exploited. Here is what each stage usually implies and what to ask before paying.
The word Stage does not describe power. It describes how deep the changes to the hardware go — and every shop draws the lines differently. Comparing "their Stage 2" with "our Stage 2" by name alone is meaningless.
The common reading
- Stage 1 — ECU calibration only, stock hardware. Nothing is taken apart.
- Stage 2 — calibration plus exhaust, intercooler, sometimes intake. The turbo stays stock.
- Stage 3 — turbocharger replacement, fuel system, often gearbox work.
What to ask before paying
Not "how many horsepower", but three other questions: on which fuel the figure was made, which parts are included, and what happens to the transmission warranty. The answers tell you more than any graph.
And ask for the full dyno sheet rather than a picture with a number on it. A figure without conditions and without an rpm trace means nothing.