FURIOUS 6 is the official dimestic title and yes... the trailer has been leaked.
[update]
Here are the official facebook page and possible poster [that is being used as its main profile image]
https://www.facebook.com/TheFastFurious6
For right now the film is known as 'TheFastFurious6' untill that trailer premiers.
I just thought of this:
THIS FACEBOOK PAGE AND POSTER MIGHT BE A RUSE IN ORDER TO KEEP 'FURIOUS 6' A SECRET
i dont want to spoil the name for everyone
FYI the song it the tv spot is the addictive 'Breath (glitch Mob remix)'
[update]
I decided to add the screengab from the leaked tv spot that features the official title...
Note [about the poster]: Poster is just a temp untill the official tv spot for 'FURIOUS 6' is released on Sunday during the 1st quarter.