The warmth you feel traveling down your spine as you watch is nothing to worry about. It's just brain melt, and you won't need the organ to survive a screening of the film.
The plot, with its multiple double-crosses and 'this group must somehow form a you-know-what' plot beats, could have been written on the back of a cocktail napkin.
Toward the end, the action becomes repetitive and tiresome, but there are pleasures to be had. Diesel is a terrific action star, in that he can give a movie a lift just by being there. Collette embraces the cold-blooded extremes of her role.
This is only slightly less dumb and nonsensical than the previous films, but it teems with thrilling action sequences and rollicking stunt work from the middle-aged Diesel and martial artist Donnie Yen.