I spoke to my DS this afternoon and he confirmed what is being said on here. I could opt to upgrade to AP2 for the difference of the current order price, my order is still not locked until tomorrow 11:59pm PDT, so at this point change fee does not apply to me. But I'm sure for this feature for existing orders that are well into production they aren't going to charge you a change fee for something they are giving you but you didn't even know existed until now.
So I asked my DS what will happen if I don't want AP2 but I do want to keep AP1, he said that's fine I could upgrade at a later date but I would be paying the difference of the after delivery change price which is $1000USD more. I was thinking of hedging my bets and not getting the new AP2, but it's a lot more than just software that you are getting regardless if you enable it or not, therefore I am highly doubtful that AP2 will ever be given for no additional charge to those that had originally order AP1.
I believe that, regardless if you upgrade the system or not, you will still be using all the additional sensors to gather information to design and improve Fully Autonomous driving, but it won't directly affect your personal experience with AP1. There may be a slight improvement in the resolution of what the camera will do for you with just AP1, for instance perhaps it will be able to differentiate a large white truck against a bright sky, where as before it had a hard time noticing the difference in contrast, but I believe it will react and behave with the same nuances as AP1 but with just a clearer picture of what it has to work with.
From what Tesla has posted about AP2 it looks like it will behave smarter and leverage more cameras to do so. I was watching some videos today of AP1 that speedup and changed lanes nearly driving into the car in the next lane over. The driver in the video had to take over because he didn't trust what the car was doing. From the sounds of AP2, it might drive more appropriately to match current traffic rather than drive with horse blinders on like AP1.
So back to my perspective comment. If you consider that if you never upgrade to AP2 or even had AP1, and you are getting AP2 sensors and computer, you're getting a "free" upgrade already. Tesla is not earning any of your money there but they are able to use your vehicle as a crowd sourced datapoint to make their AP system better and the FAP system a reality (hopefully). So if you have AP1 and are wishing that Tesla is going to be so kind and give you functionality of AP2 for free, I'm fairly confident they are not. There might be a "free" preview period like they did with AP1, but I haven't heard of anyone that had an order in flight just before AP1 was launched that received AP1 as a no additional cost update. The fact that Tesla is willing to put in - let's just assume $2000 in - hardware regardless of whether or not you order AP tells me that Tesla is already giving everyone something. From a business perspective they are adding to costs and not realizing any margins if users do not enable AP. With that in mind you can almost consider that of the $3000 you spend on AP1 on current orders is actually a $1000 margin for the feature on top of $2000 hardware, and let's not forget they still have to pay programmers even if it's not a physical thing you're getting, a top notch programmer/developer is not cheap. So upgrading to AP2 (from AP1) for an additional $2000 on top of your order, is really paying for the development costs of AP2 and whatever might be left over maybe can be considered profit margin.
Anyway, I work in a technical field and I understand that a sole purpose of a privately held business is to earn money and turn a profit for investors (of which I am one). I do not believe that Elon is nefarious greedy monster that turns out an inferior product. I believe he is a visionary that is willing to sacrifice some traditional business practices to produce a product that will change our perception of things and make the world a better place. Think of what he has done in the automotive industry that has the rest of them worried. He's done away with the dealer model; he's able to create interest in products that people might not get for several months and even years after placing orders for them; and he's able to give every product a personal touch by allowing the consumer to customize it to their specifications. Go to your local MBZ, BMW, Audi, Lexus dealership this weekend and see if you can get a vehicle that is exactly what you want in it and how you want it to look, probably not going to happen. Then get the price and I bet you, there's not way you're ever going to be confident that you received the fairest price for that vehicle. Elon is here giving his customers options they don't even know they want yet and not charging for them until they are ready to take advantage of them. That's insane! And that's why I've just convinced myself to upgrade to AP2 on my build. Damn it I'm spending an extra $2000 to save $1000, but if my intuition is right, I am saving money now by not waiting for a free handout that likely won't happen. Again, remember the 1month AP1 trial period - no one has ever received AP1 for free.
Sorry totally long reply, but I'd hate for most of the people on this thread to be angry that a free upgrade to AP2 never happens (or have to waste an extra $1000 post delivery for the upgrade). The fact that they are giving us AP1 still with AP2 hardware is a plus in an of itself.