I actually saw this tonight. Having never seen any of the previous films in their entireity I have to say I did enjoy it. From the discussions I had with some mates I saw it with who do follow the series it took place after the second film but before the third. Any fifth film would possibly be about Vin's time in Tokyo before we see him at the end of Tokyo Drift or it would be set after we see him in Tokyo Drift and carrying on his adventure in Tokyo and whever else in the world the guys go.
I have to say I did notice the cut during the head meets wall scene and it was quite obvious, even my mate said to me "it looks like they cut something there".
Paddy 
