kk u kinda lost urself vikrampatel. If u have a factory alarm system or aftermarket with start. The unit should have a GROUND out when armed, that would be wired to a relay, and the relay will sit between the key cylinder and the starter motor. When the unit is armed, there is NO way that someone can start ur car, unless they cut the relays ground off. As far as push buttons, 04 TSX uses an RF key aka immobilizer at the key cylinder. So there is no way u can start ur car without the key in the ignition, unless u wired up a Bypasskit to be active during remote start AND during push button. When u do push button starts, u require alot of knowledge in electronics (relays, diodes, power etc) cuz u need to power the ignition, acc, and start without key. If u use ur key, and put the key into ignition, then push start, its easy as cake.