Responded already very appropriately however would like to add from my side too
1 AC more than good no matter whats the situation (no exceptions pl) and with full load. Almost equal cooling both at front and rear, side vents strong blow as compared to the inner ones.
2 For a reasonable listener its more than required rather heavy sound system (VXL variant). However two additional 2 could be installed in rear doors with company wiring n duly supported by the player (fader system).
3 Would prefer 3s for everything due to quality etc. Your 3s dealer would guide you better on the warranty issue since they would be entertaining the same if any issue arises.
Point 4 and 5 could be best answered by Karachi members and excise.