Thanks for posting your vehicles Trix, it will help folks to give their opinions. Without doing a test spot on your vehicles (see, I can learn Mike), here is what I would suggest.
Buy the kit that gives you the stuff you need. Based on the size of your vehicles, I would say you need 2-3 orange CCS and 2-3 white pads plus a blue or grey finishing pad. I now personally prefer the hydro tech pads and if you go that route then the same - 2 or 3 of each plus a finishing pad. Not sure if AG offers a package yet with the Hydro Tech. If you want to go with those, you may need to give Dwayne/Meghan/Bobby a call and ask what they can do.
I am going to assume that the Saab is not bad enough to warrant yellow/wool pads. I wouldn't spend the money on those unless you know you need them for sure.
As far as polishes go, if you are a beginner at machine polishing I would recommend the wolfgang system. They are currently on sale on the special values page for the swirl remover and finishing glaze (which is really a finishing polish). They are essentially foolproof and do a fantastic job. If you have used a machine in the past and don't have a learning curve, the megs 105/205 are great also, I just found that concentrating on the polisher and pad instead of the polish itself was easy. So both polish systems are great, I just found less to worry about with the same finish worked for me.
As far as the actual polisher, again I personally like the additional power/torque the griots gives over the PC. Neither is a bad choice however. Some folks prefer the Porter Cable name over Griots and purchase based on that.
So to summarize, if possible my opinion is go Griots/Hydro Tech/Wolfgang.
Happy polishing!
You will also need some pad cleaner, but most come with xmt in the package.