immobilizer & safety

[trippin]

Hi all,

I just got Audi 80 1994/95 petrol ... full electrics and airbag etc...

I am trying to work out if this model had built in engine immobilizer or
how can I check this?

There is a light next to the ignition keyhole but doesn't seem to switch on or off... and no key control for immobilizer but it has central locking ...
the guy that sold me the car says these models come standard with built in immobilizer which switches on when u take the key out...? Is it true or?

Otherwise I need to know to make sure I put one in ... any ideas?

Also this car has old radio with CD stacker in the back ... but the radio looks crap is it possible to replace this radio with modern unit and still be able to control the stacker in the boot ?

Thanks