Do talk to Aaqib about this @Machizmo.
I recently got a Corolla 1.6 Altis done from him and the difference is night and day.
Overall the improvement should be in driveability, throttle response and fuel economy.
Peak power figures don't do much for your daily drive.
For example, the problem with the corolla was excessive lag in the mid range (3000 to 5000 rpm) in daily drive and no response on the throttle, until the gearbox dropped to a lower gear and then there was sudden acceleration.
All problems were fixed and the car is running great now.