Makes sense @gotcha640. Thanks for the same.
To clarify, I own a small hatchback (Suzuki Alto) to help me through the back alleys and ruthless traffic in India
Since its under warranty, the showroom guy warned me against making any mods to the vehicle as such; including any cuttings and fittings.
I too didn't feel like doing it any way. Hence I stand with a dash that would allow exactly 4" speakers only. So I went for the auditors.
Unfortunately the doors dont have a provision.
As suggested by @stevenred, I am now going ahead with plugging my 2ch Amp into the front ones and purchasing a better one for the rear.
I did try to fit in a small 8 or 10" sub but then it eats up so much of the boot that I wouldn't be able to carry a decent sized duffle bag for the occasional long drive.
So it stands out of question for me now. I do understand that I will miss what the sub could have added to the acoustic environment but I will have to live with it atleast for now until its outta warranty.
Once it is, I will surely think about some 6x9 (maybe, components) in the front, possibly door mounts along with a sub if I could manage a custom mod to fit that in (I am thinking about the spare tire tray for this one
So far the sound's been very good, a bit of tweaking with the balance and fader and I can happily say that I do get some very good positioning of the audio.
Thanks everyone for all the help. What a start!
I would like to sign-off with just one last question - I heard from people that dash mount speakers pointing straight up, directly into the windshield actually spoil the sound. But a lot cars come with a dash fitment for front speakers so I don't understand whether this makes any sense. Probably a short note or a link to a useful source would be very helpful.