1. What would be the ideal set up for good performane? 1 HU, 4 Channel AMP, 4 speakers in the doors plus 1 Subwoofer. is this right?
The speakers dont need to be on the rear door always,you can add a good thick parcel tray & mount speakers on them,they give a good effect,but if you think its going to be a prob cos of the small boot them having them on the door rear door will be fine.
For the front door go for component speakers,you can add a 5.5 inch component which fits well into the swifts door or with adding a custom spacer you can add in the 6.5 inch component speaker,such as the one given in the link Rockford Fosgate® (India) : Car Speakers System India, Best Car Speakers India, 6.50" Prime 2-Way Component Speaker System
2. Can i buy integrated HU alone from Maruthy and fix the AMP, Subwoofer and speakers out side? cos i want the dashboard to be perfect
Yes you can do that but you mite have to add a separate equalizer or Woofer control to tune the system to your taste.
3. This is the Specifications of integrated HU. Is this good enough to fix a 4 channel AMP, subfoofer and good speakers outside?
The stock system on the new Swifts are pretty decent,
so when you pick up a 4 channel amp ,2 channels from the head unit are connected to the amp,from the amp two channels will power the front components & two channels from the amp will be bridged to power the woofer.
Remaining two channels from the headunit can power the rear speakers.
You can use a decent 4 channel amp from Sony (XM-GTR7040 : Xplod™ Amplifier : In-Car Entertainment : Sony India
) or any brand you prefer.
4. what capacity speaker should i select for good performance? can u advise the Specs?
Dont look at max watts,look for the rms of the speakers,speakers with 40 rms or above can perform well.But diff speakers have diff sound qualities.