We are looking to update the Store details when we release Horizons to help clarify this, its slightly complicated because there are Bundles we sell which contain Licenses to unlock parts of the game.
Anything with 'Edition' is a Bundle. The ED Arena Edition allows people to purchase just Arena, ED Standard Edition allows people to purchase the current 1.x game. We'll be releasing some Horizons Bundles to allow people to purchase Horizons.
Everyone gets the Elite Dangerous Physics Engine (which on Horizons launch will be changing name to Elite Dangerous Core) and controls the flight simulation and physics behind all Elite Dangerous titles.
Elite Dangerous: Arena gives people access to the Arena content - this will appear in your My Apps & Games.
Elite Dangerous gives people access to the current 1.x content - this will appear in your My Apps & Games.
Elite Dangerous: Horizons (when it launches) will give people access to the 2.x content - this will appear in your My Apps & Games.
So long as you have the Elite Dangerous Physics Engine installed and the others 'ready to install' you should get access to which ever flavour of the game you purchased.
We'll put an FAQ up on our Support pages when Horizons launches.
Thanks for the clarification Gary. I'm relieved to hear everything is in good order. Sorry everyone if i started any confusion. I Love the game and want to help where I can. I may have been a little overzealous but that's only because I care.
As for those asking how I felt it improved the game id be happy to explain. And based off of the Light Gary has shed maybe these were just coincidence. I was able to find Arena matches. My Galaxy map felt like it loaded quicker and super cruise transition felt smoother. A friend of mine before he installed the remaining 2 items was getting messages in game that said Something along the lines of "there are too many people playing online with unofficial versions of the game and you might get kicked". And he did get kicked a lot. When he installed the remaining 2 items it stopped happening. Maybe people hadn't downloaded the latest patch or something.
Anyways I appreciate the quick reply and explanations.