Thanks to Jim for his informative response.  I'm particularly interested in any information that he or anyone may have regarding the following modification(s) being referred to:
From Jim Hergert,
.... In fact the factory is coming out with a  tail stiffing mod. that adds about 2 inches to the leading edge of the vertical stab. and a much bigger dorsel fin going forward to help strengthen the tail torsorsonal resistance. It looks much better too. Just do a vertical Hit on the tip of you Horz stab. and watch the shake. Then do this on the Tandem, you wil see the difference and why they will probably require this on the turbines.....

regards,
Joe Trepicone IVPT

Hi Joe,
The first airplane with this mod. is presently in Paint and on the fast track to be at OSH. It also has the Ice Zapper deice system. A lot of work to make OSH. I'm sure if it is there they will tell you all about it. I did the test, above, and it is much stiffer. Get ready to add some weight and safety to your spine. BTW, I also heard about a flying turbine with 150 hrs. that had to replace ALL of the hinges in the tail, yes, wore out. Something going on back there.

Jim Hergert
N6XE, "An Sex Y" L4P