Bhai, ok, let me tell you something in detail. The pre installed JVC player that comes in Liana is prety decent, also the speakers at the back are good quality. Its just that the speakers at the front doors are shit and doesn't support the system.
I would suggest that you kep the Player(which you will
) and also keep the speakers at the back also. Just get a component system of Kenwood, which will cost you around 8k, it would have two speakers and two settelite tweeters. Just put the speakers on the doors by replacing the shitty ones and put the tweeters on the dash board as they come with a nice stand that would be attached by double tape. and if you can have a small amp (around 200W) you will get very decent quality sound with no Alterations at all..
The front door speakers that comes with the car have plastic cover to fit correctly to the doors. With component speakers just tell the fiter to make 1" thick wood plate to get the fitting right. He will put the wood plate to Doors and speakers on the wood plate..
phew... I have had a sound system fited in my liana and it took about 4 hours to do so, but its a rather complicated system.
I hope you will like the sound quality, as per my suggestion.. Off course its always your choice that matters the most.. Take Care...