The factory equipped tyres in the Swift are supposed to be fuel-efficient tyres, so naturally, they produce a lot of road noise. I also felt that they do not absorb bumps that well. You can try reducing / increasing the tyre pressure but will not help that much.
Can do two things, you can just live with it, or just change the tyres. There is a day / night difference in the driving once you change the tyres. I know people criticize that these are Bridgestone tyres and not the local ones so why bother changing, but believe me these Bridgestones even let you feel the small pebble on the road, and for what, just 1-2km per liter better average than the comfort-oriented tyre?
Lastly, stick to the manual provided with the car for any sort of maintenance (oil changes, tuning etc.), and you will be good for 4+ years. No need to do any sort of experiments.