I think designing a light aircraft in this day and age without a Kerosene burning powerplant (or a future option to have one) would be a huge commercial mistake. The new Thielert Centurion V6 235hp would be an awesome combo.
However for reasons stated, it more than likely it will be Lycoming powered. Anyone know if
they are developing a Diesel?
I also think that Thielert wouldn't risk their commercial future by marketing a diesel engine in the USA, before it has been thoroughly tested by European guinea-pigs.
The Diamond DA-40 & 42 Twinstars are shipping to the U.S. with the 135 hp Thielert engines, so they will know all about Centurion powered aircraft by the time a new Cessna starts production.
Im hoping they will offer a V6 conversion for the Twinstar! /drool