I had a Unichip for a few years.
After fitting and tune there was about 15% more power and torque, boost came on earlier, fuel consumption was a few percent lower, and reduced black staining around the exhaust caused by the usual stock tune which is over rich.
With intake and exhaust mods and another tune there was more performance.
If you have the boost module it prevents overboosting if properly set up.

For a GC8 there may be cheaper ways to get similar performance but if you already have the correct version Unichip then keep it.