The difference in the polishers is really how they operate. The Flex is forced rotation, meaning it is similar to a rotary but rotates randomly. If you put a lot of pressure on the Flex the pad will not stop spinning. There is more user error with the Flex and if the pad isn't held right on the paint it will try to "walk" on you. Is it better than a Rupes at correcting? Not necessarily. The "throw" of the Rupes allows it to spin the pad at a larger pace than the Flex. The Rupes also requires zero pressure. The Griots BOSS system is a copy of the Rupes, but with a lifetime warranty. For a weekend warrior or enthusiast, a Porter Cable or Griots 6" random orbital are great entry level polishers. The good thing about the Griots is of course the lifetime warranty and more powerful than the PC. I own a Griots 3", Flex 3401, Flex Kompakt, Rupes 21es, and a Rupes Mini and I prefer my Rupes over everything else.
Waxes won't do anything for the scratches. I detail on the side and hardly ever use waxes anymore. I even have a few high end ones that aren't any better than the good cheap ones. Some Collinite 845 works great and is cheap, but I would just correct the car and coat it.
I also don't recommend m105/m205 for anyone that hasn't polished before. Why? Because it has an extremely short working time and anyone with out experience will over work the crap out of it. Get something like the Blackfire Duo -
http://www.autopia-carcare.com/blackfire-duo.html#.VfLZnLS4kdU.
Call Autopia Car Care and ask for Ray Vega - 877.855.3125 - tell him XxBoostinxX recommended you and that you need some advice on some products. He is extremely helpful and will take the time to point you in the right direction. If you sign up I get $5 of reward points.
http://myaccount.autopia-carcare.com/mod_referralRewards/welcome.php?referralCode=RXWYQF