Going 1" longer in an DYG SL shafts will soften the butt frequency of the shaft somewhere between 1/2 to a full flex, but it doesn't change the tip frequency of the shaft.  The butt frequency is what you perceive as the stiffness of the shaft, and the tip frequency will be how the head goes through at impact.   It will depend on how high you hit the ball, if you are trying to lower spin, and how you like the shaft to feel.  When you get fitted for your irons, that is a great discussion to have with your fitter.  If you are looking for a good local fitter, give us a call and we would be happy to help you find one in your area.  1-888-TITLEIST.

Is 1 inch long and 2* upright the same as your current irons?

 If your current set is standard, 2* upright means the 5 iron will have the lie angle of a 9 iron. So Imagine your 9 iron being 2 inches longer(this would be a 5 iron 2* upright), then add another inch for the inch longer.