How do you take an factory fitted immobilizer system out of a car?

Depends what kind of car it is. If its a 90s GM, Chev, Buick ect.. You can by-pass the immobiliser by attaching a resister to the two wire sensor that goes to your ignition switch. Just measure the resistance of the chip in the key with a multimeter and buy a resister that matches at any electronic store. Then cut the two small wires that lead to the ign and put resister inbetween them and presto! Your car starts!