The Fiesta ST v.s. the Focus ST is a completely different class and argument v.s. the 1.6 L N/A Focus v.s. a 1.6 L N/A Fiesta.You should read a review made by @dyn085, he owns a FoST and a FiST... He's taking the FiST over the FoST
Regarding refinement, the Focus also has four wheel independent suspension vs. the more primitive twist beam rear axle on the Fiesta.The Fiesta ST v.s. the Focus ST is a completely different class and argument v.s. the 1.6 L N/A Focus v.s. a 1.6 L N/A Fiesta.
The Focus is a more refined car than the Fiesta. It is also more practical.
With the same engine though the Fiesta would be slightly quicker due to being lighter.
In your market I believe the Fiesta Sport is equipped with the 1.0L EcoBoost, and the 1.5L for your market.what would you prefer between a 2013 ford focus trend 1.6L hatchback and a 2013 ford fiesta Sport and why?