This is software and equipment to get on with GM cars (2003 Monte Carlo SS, and a 2009 Cadillac STS) for diagnostics and programming.
In order to perform "advanced functions" on GM Vehicles you are going to need something that talks with all the computers on the GM Vehicle.
The ones that I know of that do this are:
1) GM Tech 2 (will handle everything including programming the computers "updating calibrations") This tool is being phased out but it's still supported until they can get the MDI fully operational. Either way this works Stand Alone without a Laptop/PC.
2) GM MDI (Some say there are limitations with some model years but others say it's better since the updates) Of course using Tech2Win to mimic what the GM Tech 2 does) - This performs like a J2534 Programmer as a Pass Thru Device. DrewTech and companies like Ease Diagnostics make J2534 Pass Thru Devices that will do this as well. And they sell their own flavor of Diagnostics Scan Software. Keep in mind only the GM stuff will do EVERYTHING for GM Vehicles.
3) Snap On Solus (This will do a lot not only on GM Vehicles but others as well. And it can do some of the advanced functions like Automated Brake Bleed on the ABS unit just like the GM Tech 2 and GM MDI) - Keep in mind there are many functions that the Snap On won't do. The Tech 2 and MDI will allows you the option to access and control everything on GM Vehicles.
There are others but I haven't seen them nor tested them.
I started out with the Ease Diagnostics J2534 Programmer with the Programming Assistant software and Scan Diagnostics Software.
However I found for programming these devices work great and they are also a good scan tool. However when I needed to Bleed the ABS Pumps on both a Silverado Duramax Dually and a Tahoe I could actuate the Solenoids and the Motor but never was able to activate the GM Automated Brake Bleeding Procedure. You can search this on YouTube to see how it works.
Ultimately I ended up acquiring a GM Tech 2 to go along with my Ease Diagnostics setup.
If you purchase Scanners that are less featured and don't support Bi-Directional diagnostics you probably will only be able to communicate with the ECU only. In some cases mid-level scanners have access to the ABS system and sometimes also the SRS system (airbag) but won't allow you to talk with the computers like the BCM (Body Control Module).
Depending on your GM Vehicle it can have as little as 3 computers and up (my wife's Escalade has 8 computers).
Also you have to keep in mind that some of the Newer Vehicles us CAN Communication. In the case of the Tech 2 you have to also have a GM CanDi Module in order to talk withe CAN Bus cars.
I don't believe the GM Vehicles you mentioned have the CAN Bus but you can look that up.
If you decide to go with the Tech 2 it can get confusing especially if you are wanting one that isn't a Chinese Clone.
The Tech 2 has been manufactured by Hewlett-Packard, Vetronix and Bosch/OTC. Regardless of which one you get they should do the job the same.
If you want official updates from GM to update the Tech 2 it will cost you a minimum of $775 per year to update. The good news is the final update for the Tech 2 has already released. If you get a scanner with this version you will never need to update it again.
AcDelco allows you access to the Firmware "Calibrations" for the computers for $55 for unlimited 2 to 3 days access. So regardless of which device that supports programming you get that's what it will cost if you need to program the computers with the latest calibrations.
Ps. If you are looking for tool that is working well only, you can get a decent one from China, much more cheaper than the dealer. There are many good China clone, esp. Tech 2 scan tools