2002 Mazda Millenia

Hello.  I am looking for some install advice for a 2002 Mazda Millenia.  The car has a factory alarm and keyless with 2 remote controllers.  I am thinking about installing a remote starter but no local installers can give me straight answers.

1) The diagram I have says that my vehicle has a transponder type theft system that will need to be bypassed.  What is a transponder?  My key doesn't have a chip in it, or is that an immobilizer?

2) They are telling me that if I want to keep my factory alarm and keyless, I'll need to have two remote controllers - the factory one and another for the remote starter. 

My question is does the 2002 Mazda Millenia have an aux channel for the factory remote controllers?  If so can't they just install an add-on remote starter?

The other thing they are saying is that if I want only one remote controller and an alarm I will have to get a remote starter/alarm combo unit, and that the factory alarm will be disabled and the remote starter/alarm combo unit will be what takes it's place.  So why replace the factory alarm which works fine with another one?

My goal is either of these two things.  Can someone out there tell me if either of these are feasable? 

1) I get and ad on remote starter which is activated from the factory remote controller's aux channel.

2) I get a complete remote start system with new remote controllers and use the lock/unlock button on the new controllers to work the exact same functions as the existing factory remote controllers (lock/unlock the doors which also activates the factory alarm)

Thanks in advance for the help