V-tail = extra speed.
With a T-tail, you have 3 big things sticking out into the airflow. 2 of which do something useful; the 3rd just gives you yaw stability.
With a V-tail, you lose the 3rd one. You also get less yaw stability, but with a plane in this class (price) you will have a yaw damper anyway.
I don't know how much extra speed this is worth but it will be a LOT. Looking in my TB20 POH, each antenna is worth about 0.5kt, and I have about half a dozen of VHF, UHF etc ones sticking out. The vertical stabiliser is vastly bigger and must be worth 10-20kt - at 150kt. At 300kt (TAS) the stabiliser must be costing many more knots.
I would have a rough stab around the 30kt mark, and that is a helluva lot on a sales brochure which is trying to draw in a few hundred position holders, each paying a big enough bundle to buy an SR22
