Start with how you use the car
Before you look at horsepower numbers, be honest about what the car is for. A car you drive to work every day needs to start, idle and behave like a normal car in traffic. A weekend car can be louder and less comfortable. A drag or track build can give up comfort completely.
- Daily driver: Stage 1, maybe Stage 2.
- Daily driver that sees the occasional track day: Stage 2 with good cooling and brakes.
- Weekend or track car: Stage 2 or Stage 3.
- Drag or show build: Stage 3 or Stage 4.
Stage 1: the best place to start
Stage 1 is a new file on the factory engine computer, with no parts. On modern turbo cars it is usually the biggest gain for the least money, it keeps the car comfortable, and most tunes can be flashed back to stock. If you are not sure where to start, start here.
Two things are worth adding early: a gearbox tune on automatic and DSG cars, so the extra torque does not wear the clutches, and an intercooler upgrade on cars that heat-soak easily in hot weather.
Stage 2: more power, more decisions
Stage 2 adds breathing parts, most importantly a downpipe, and a file written for them. This is where you have to think about the law: a downpipe without a catalytic converter is not road legal in most countries. Choose a catalysed downpipe if the car has to pass inspection, and check whether your gearbox or clutch needs an upgrade at this torque.
Stage 3: a different kind of project
Stage 3 means a bigger turbo, and usually a better fuel system and gearbox to go with it. The turbo is often not the most expensive part of the job once you add the fuel system, gearbox work and labour. Many Stage 3 files are designed around ethanol fuel such as E85, so check that you can actually buy it where you live.
Stage 4: an engine build
Stage 4 means rebuilding the engine with forged internals so it can take much more boost. It is a project for drag, roll-race and show cars, and it works best when one shop builds, tunes and stands behind the whole package.
Five questions to answer before you choose
- Will the car still be used every day?
- Can I buy the fuel the tune needs, every time I fill up?
- Is my gearbox or clutch ready for the extra torque?
- Does the car need to stay road legal and pass inspection?
- Have I budgeted for maintenance, not just the tune?
Our advice
Start with Stage 1 and a gearbox tune, drive the car for a few weeks, and log how it behaves. Most people discover that Stage 1 is all they need. If you want more, you will then know exactly which part is holding the car back, and our guides show what each next step asks for.