As this is a turbo motor, there is no such thing as "too big" for an exhaust. I and many others run 3" exhausts in this car with both stock and upgraded turbos. IF it was a naturally aspirated motor, the exhaust can be tuned and sized (along with a catalytic converter) in order to have pressure waves that help with exhaust scavenging and flow.
Do not worry about it.
Welcome to the forums!
EDIT: If you also are running without a catalytic converter or an upgraded one, you may want to get the tune of your car adjusted to compensate: There is a potential to overspin the turbo since the air will flow faster/freer than the stock tune is setup for.