I am interested in the D2 and I would like to know what the best shaft for a 80 mph. swing speed would be?

It really depends on your tempo and your desired ball flight, Chris.

Do you have a quick, choppy swing from the top, or a long, lazy swing?  Do you fight a hook or a slice?  Is your current ball flight overly high or low?

PS, everyone here will tell you to "go see a fitter" and "get custom fit".  Of course, that -is- the best course of action, but we are happy to help with some advice here, as well.

I am 68 and my I suspect my swing speed to be somewhere around 80 to 85 mph and I am going to a club fitter in January to find out the answer to your question. I currently have stiff shafts in my irons and will probably go to regular or even senior (soft regular)shafts depending on my fitting. I am also not ruling out going to graphite shafts in my irons but will weigh distance and ball dispersion with steel vs. graphite. I do have regular flex graphite shafts in my driver, fairway wood and hybrids and am pleased with the distance I get with my slower swing speed. I had shoulder surgery July 1 and am just now starting to hit balls again. I figure I should be 100% in another month but with old man winter coming don't know how many days of golf practice I can get in before I go in for a fitting. New clubs are definitely in the picture as a reward for the golf down time I have experienced.