You can see that the guy in the video is letting his sticks bounce as he does those "double strokes" (they're not really double strokes--you can see his back fingers coming off of the sticks while he plays them). Notice how uneven and inconsistent it sounds? If you want to play that fast and have it sound good, you should work up your single/double/triple strokes, legitimately. It will probably take you a couple of years, but one of the cool things about drumming is that there is always something to work on/up/towards. And, when you finally get your chops up to par, you can play some amazing stuff that will sound MUCH better and cleaner than this guy...
I agree alot with Caddywumpus, Tiger here is a great example of what not to aspire to. However we can all come at you through text and words and none of this may every really help if you don't actually see it and work at it every day until it becomes 2nd nature. I studied with Tommy Igoe who is a Technique Nazi and all about finger technique, some guys are more wrist. I have learned to blend the two depending on what I am playing.
The best thing YOU can do is find a REALLY GOOD Player/Teacher (someone who plays professionally for a living) in your area who you can see on a regular basis, and learn from him. I (as a teacher) would suggest not to go wild on your own with nothing more then a rudiment book to "fix" your situation. Knowing ALL the rudiments wont due you one damn note of good if you can't speak with your hands clearly.
The old saying "practice makes perfect" can't be further from the truth. "PRACTICE MAKES PERMANENT!!!" IF YOU PRACTICE SOMETHING WRONG, YOU LEARN IT WRONG!!
I thought it said you were playing 6 years.......6 months.......give it time. I'm playing 16years and I aint even scratched the surface of what this instrument can do. Never the less, I stand by my above statements. If you want to progress faster.....finde a pro, learn learn learn!
"There is no substitute for a GOOD teacher" - Ted Reed
Good luck!