Are the engines the same in the 2013 Prius with just changes to options such as seats,stereos between models
Yes, 2013 uses the same 1.8L as 2010+. Also, the engine in a 2013 two is the same as what is found in a 2013 three, four and five.
The engine in the Lexus CT200H is the same as well. They just have different programming on the ECU. Not sure if they changed the final drive ratio as well, like they did with the Prius v. SCH-I535
If I remember correctly, the mpg of a Prius C isn't any better than the Prius Lift Back, one would think that a smaller engine would yield better mpg.
The c does better in the city, but give it all back on the highway, to yield the same over all MPG. Small engine is more efficient in the city, but less on the highway. It is a compromising game...