@suryaputra,
I think its more of a centering problem. Try this- take the Baleno on a flat highway that you know is fairly straight and let it cruise at over 60kmph. You will see the car moves slightly to one side. Correct it. Now the car should move to the other side. This is either slop in the servo in that its not centering correctly or a bushing in the steering linkage has degraded (which would be stupid for a 20 day old car). I have already reported this to the ASC and they will check it like ice_wise said. That being said, I am going to get the ASC guys to check my wheel balancing and alignment. Sounds stupid to do it so early in a new car but if the car can have a faulty compressor and alternator from the factory, anything is possible.
With regards to the bumpy rear ride, I think the gauge at my regular pump is miscaliberated. Yesterday I put in 29psi in a fairly warm car and today it showed 31psi at about the same time in the afternoon but at the nitrogen fellow who is also a reputed tyre supplier for Bridgestone. He suggested to check the pressure with nitrogen after a week at his gauge again to see if the pressure has gone up.
Something I forgot to mention in previous post. I parked up, pulled the handbrake and as I was getting out of the car, I heard creaking from the rear left side. So I swayed the car and sure enough, there was creaking there. Creaking sound akin to an old wooden bed makes when you move around on it. I got out and pushed the car and the creaking was still there. I got in, dropped the hand brake, then raised it again and tried to sway the car, no creaking sound now.
Also, if you do release clutch incorrectly and have the car jerk in gear, you can hear the clutch chattering outside the car. The sound is similar to the sound of engaging gear but its frequency is the same as the clutch engaging and disengaging rapidly. I used to have sticky clutch problem in the Swift for the first month or so, not sure if this is similar
Just weird
Ameyam