Amit ji
Please check out the following link
http://www.team-bhp.com/forum/ask-gu...io-thread.html (SX4 ZXi - Integrated HU Audio Thread!!)
then you can check out my query (im in the same soup as you only im getting a dezire which has the same Stock HU as your SX4)
http://www.team-bhp.com/forum/ask-gu...dzire-vxi.html (Am i Doomed With respect to ICE in DZire Vxi)
Lastly the installer prices are a little off
i would suggest you get GTO607 componets for the front (these are 6.5inch compos but should be able to fit with spacers) these are for 6500rs with bill , you should be able to get a 8-10% disc. these components sould be AMp driven
now for the rears i suggest what im plannig
Leave the speakers on the rear doors stock-and run them off ur HU
now add an amp in a sealed/ported ( depending on your tastes) in the boot and drive it off the amp
i would like to mention that im an ICE novice too.
So the above is not exactly "guru" advice
Lastly please inform me of your install i would love to accompany you since im gonna be doing almost the same thing very soon!
P.S - Good installers are FM Drive in SAntacruz , Boom in Bandra and theres a chap at opera house/lamington rd too (i can find out more if your interested)
PLs check
http://www.team-bhp.com/forum/ask-gu...n-suburbs.html (Reputed ICE INSTALLERS in Mumbai Western Suburbs)