What is needed for a remote start with a microchip key?

Depends on the car. Most cars use a universal module called a "556U" With this module, you put a chipped key in the module which was a wire that wraps around the key and the other side wraps around the key cylinder so the car thinks the key is in the cylinder. There are new modules that have just come out that interface with the car's immobilizer system that store the code in them where the person does not need to lose a key