How many tour players are using the 913?

In the first two couple of months around 80 players put it into play. Generally the process starts in the last week of June between the US Open and Open Championship and it is a two-month process.
On the European Tour 50 per cent put it straight in the bag at the French Open, by end of the season 90 per cent are expected to make the change. 

Which will be more popular, the D2 or D3?

D2 will outsell the D3 2:1, initially will be 50:50 with the hardcore players, then it will follow the more appropriate pattern with the more forgiving D2 being the more popular.
The D2 model will be the more popular of the two

Can I still use my 910 shaft in the 913?

Yes, you can interchange the shaft from your 910 to the 913. 

Interestingly Titleist sell a huge number of shafts and 7-8 per cent of players buy a separate shaft.

How long is the shaft?

The longer the shaft the more it will generally generate more clubhead speed but swinging it the same is the challenge.

Titleist have done tests where players who use a 45-inch driver try a 46 and their swing speeds go up. But when they come back a week later their swing speeds have gone back down as they start swinging slower.

Titleist believe 45 inches is the way to go, interestingly the average on tour is less than 45.

• The new 913 D2 and D3 drivers will be released in November. Both are available in 7.5, 8.5, 9.5 and 10.5 while there is also the option of 12˚ the D2.