Really brilliant comment.
I think the elephant in the room here is that people think they know what the news is and are assuming a sell on the news but on average I think people really don't know what the news is and that assumption is going to get punished. This isn't a case of hype about a known or well-guessed outcome - like AWD or the Model X - and as a matter of fact TSLA did go up on the Feb 2012 news of the 2012 Model X unveil and Model S reservations spiked to go with it - and the unveiling of the PowerWall and PowerPack seeded the main 2015 rally that peaked at $279.xx with another top at $282.xx
Cars are such emotive things that have been subjected to $billions upon $billions of incessant public brainwashing - such that it is for example common knowledge and received wisdom that you can't have a car that looks like a Ferrari or a Maserati without paying Maserati or Ferrari prices for it - but there is no such inherent cost-penalty linked to pretty shapes to bend metal into unless you have to design a mid-sized car around an ugly lump of an engine block in the front assuming you still want seats in the back or when your main design objective is to stop the cheap models in your lineup appealing to wealthy buyers that would pay more if it wasn't so damned ugly. Look at the BMW i3 and the GM Bolt. Did they need to look like that? Yes they did - or else they would attack sales of better looking ICE vehicles instead of confining all possible interest to a tiny niche of hardened tree-huggers. Tesla does not have either of those problems - neither the engine block (and ugly radiator grills or exhaust ports) to work around in the design nor the desire to protect sales of more expensive ICE vehicles. Tesla actively wants to compete with ICE vehicle sales to the max and there is nothing and no incentive to stop them. Most likely the Model 3 is nominally $50K - $100K more beautiful than anything on the road at its price point because there is every advantage for Tesla in doing that and no downside - elegance and aerodynamics tend to go hand in hand and if you're going to bend metal anyway you might as well bend it pretty. That is just item number one on the list of unimaginable shock and awe.
Anyone that says that a $35K car can't look like a Maserati is only saying that because it has never happened before - i.e. the very definition of an expert trap. Seriously, auto industry experts will howl and declare that Tesla is inexperienced and stupid to threaten the cannibalization of its $100K cars with such a beautiful machine but in the eyes of the mainstream consumer - here is a $100K car for $35K. A total no-brainer compared to a $35K ICE machine while Tesla's $100K machines take on a whole new mantle of brand prestige by association for those that can afford it.
Next up, performance you can't buy for the money anywhere else. Unmatched running costs without settling for a tiny-engined econobox or a slow as a snail hybrid. Interior space, cabin technology, OTA network integration, autonomy options, safety and handling, no dealers, no emissions, no pay at the pump....
I have absolutely no idea how Toyota hopes to maintain customer loyalty to its Prius division (already 11% down in 2015) that and half of its Lexus division two weeks from now and Toyota and Lexus and all of the shorts that swear by them have absolutely no clue what is about to hit them. As for Toyota's hydrogen FCV push and shunning of EV technology, that I expect will hurt the entire Toyota brand and descend rapidly into a business-school textbook example of corporate mismanagement for the ages.
I would maintain that the way to play this is to buy any pre-annoucment dip and go long and strong through this particular event.
Disclaimer. This is my private opinion that is only as good as the reasons given for it and the reasons given are subject to error and omission unknown to me as well as omissions known to me and excluded for brevity any of which could prove material and render my opinion materially wrong. Not investment advice.
Geez I hope the model 3 isn't as good as a 100k car or no one will buy the model S! As I posted above I think TM knows this and will have an answer for differentiation on the 31st. The evidence is the known 100kWh version, and the "changes" being communicated about pricing and such. So at a minimum we should see on "3 day"
1) crushed velvet jacket
2) unveiling the car, looks nice.
3) specs for car, probably exactly what we expect (200 mile range at bottom end, something else probably 260 top end)
4) some new feature comparable to the big air filter. Nothing FWD fancy, but some feature to chew on no one expected.
5) comment on reservation numbers, maybe. If there is it will be like "OMG it's 40k" (audience sort of woo hoos, everyone expected higher) (I think partial day reservations, from live stores will be less than impressive--just has to be)
6) one more thing.... the model S is getting it's own changes! New front end revealed, new feature or two, better console, another cupholder, and 100kWh ("By the way, they have been shipping for n months! All 90's were really 100"). Base price of S is now 7k higher since they know the top end 3 will be 65k and they need to make sure they don't overlap.
This doesn't even include any zany theories. I really think model S differentiation is baked into the 3's existence. Otherwise S buyers would start to wait-and-see for 1-2 years.
Tin foil theory:
7) "By the way, Q1 shipments were 17k since we did so many X's". After all, that announcement is due soon anyway, maybe it makes sense to do it here. This signals that they DO care about the stock price since they could have just waited. If the news was good, they would know it now, and this would be the way to do it I think.