Of the most important items of note (that should come with every 400+cc driver) is that to use these clubs you MUST be flexible. I can't stress this enough. The day after hitting my new 400cc driver, my back muscles were tight.....and I consider myself above average in flexibility. Yes, it was a cold day that we played, and my motions were restricted by layering of clothes, but the issue still needs to be addressed.
There is only one time when you stretch to increase your flexibility: when your body temp is heated up. For example: look at your body as an ice cube; when it's cold its hard (inflexible); as soon as you warm it up it relaxes and melts (flexible).
The times I stretch is right AFTER a hot shower in the morning, and right AFTER exercise. Too many injuries occur by stretching cold....so don't do it....I don't care what any body tells you...don't do it.
Let's apply this to a day of golf. In the morning right after a shower, stretch. When you get to the course, hit some balls (preferably with your wedge), stop and stretch a little, then continue moving up the food chain with your clubs...each time stretching after each club.
Now, if you've never stretched before, one day of this is not going to do much for you, but if you make it a habit in your daily routine...say every time you get out of the shower...you will see fantastic results.
The reason flexibility has become so important is because of these new drivers. They all are equipped with longer shafts with the purpose of leveraging the swing speed. This all comes at a tremendous price to your back, which already hates you for playing this game in the first place.
Pay attention to what your body is saying, and you will have much more enjoyment playing with this new equipment.
Thanks for reading, keep it in the short-grass.