There are a couple of different SIRIUS Starmate that are out there, and some are not compatible with each other. It is good to know which receiver works with which kits:

Original Starmate-ST1

MODEL Number ST1 .This was the first starmate that SIRIUS came out with. The unit featured a channel toggle switch and a bright 3 line display screen. This unit has since been discontinued.

This is the Starmate Replay MODEL Number ST2R or ST2. This was one of the first SIRIUS receivers to allow the PAUSE, FAST FORWARD and REWIND feature. This feature allows you to pause LIVE satellite content and restart it with out ever missing anything. This unit has also become Discontinued.

Starmate ST3- MODEL Number ST3. This was one of the first receivers to introduce the Universal SIRIUS Docking style. This Universal docking style has expanded compatibility for all the SIRIUS Dock and Play receivers made currently. This receiver did not include the Replay function.

Starmate ST4- This SIRIUS Starmate 4 was an upgrade to the ST3, adding features like Pause, Fast Forward, Rewind. This receiver did add back the Replay function and also added the Blue Screen.

Starmate 5 ST5- This is the newest Starmate in the SIIRUS Receiver arsenal. This receiver keeps all the same features as the Starmate 4, but adds one very cool trick. This receiver can access SIRIUS A La Carte programming while currently no other receiver can.

These are the Starmate lineup from SIRIUS. If you are looking for a part for these receivers take a look here: