X stiff is the way to go for you. I too have a fairly high swing speed measured between 108 my slowest and 112 my highest. I bought an R11 9.5 with a stiff shaft based on the assumption that it would be the same set up as my burner. I could not hit it as far as the burner so then I went to a really good club fitter. They swapped the driver for another R11TP 8 X stiff and tuned it. I began carrying the ball 275-295 with ball speed coming of the club between 165 to 172. I also had the rest of my clubs fitted. I have dropped over 8 strokes on my handicap over the last year.