Just wonder the replied so far can simply give you solution without asking for more details.

Before u jump into it, you need to clarify the area/problem you want to improve:
Simply said, what causing you want to sound proofing your Wira?

1. Tyre noise (Front or back?)?
2. Road roar?
3. Engine noise?
4. Wind noise?
5. Traffic noise?

There are sound absorbing, sound deadening and sound reflection. Each areas need different treatment combination.

The popular brand with high C/P ratio is STP currently, but seriously 500-600 won't get you a satisfaction result if you know what is 'sound proof'.

Actually most of the low end car suffer road roar problem. From what u said, road roar is a low frequency vibration noise caused by contact of tyre with the road, that noise frequency range is around 100-300Hz. Based on my own experience and judgement, this noise is caused by few factors. 1st, a hard tyre. Change to soft tyre u will immediately feel ur car is more airy, but tyre won't last long, after 10k the tyre become harden and the noise will come back again. The main contributor of this noise is due to bad suspension design. The suspension is not isolated well from the chassis and  just can't absorb those tiny bump of the rough road, causing the vibration of the tyre transmit through the strut to chassis, and then causing ur whole chassis (floor, roof, door panel) to vibrate and resonant at the same frequency. This noise is annoying, it will kill ur ICE midbass sound, and kill ur ear in long run (highway drive). Basically u can't solve this problem by changing suspension, and will become worsen when u change ur rim to larger size(hence thinner side wall) and spring/absorber to sport type. The only way u can do is using mass to dampen the chassis vibration, where u can apply thick dampening sheet like STP gold to the whole floor panel. However the main problem of that is ur Axia adi a underpower car, adding mass will make it more worse in terms of power and fuel consumption.