The CT Sport Plus was a run-out model only available in 2017. Its been discontinued because of the facelift in 2018.
The differences between the pre-facelift and facelift models is dependent on trim levels, but essentially, they've changed the bumpers and grills and the specification levels. All facelift CT's come with a mesh grill. Only F-Sport variants of the pre-facelift ones have the mesh grill.
As the trim levels go up, you get more kit as standard. Some of the trim levels overlap. Essentially, Premier is top spec, S is lowest spec and Luxury mid range. F-Sport is similiar to Luxury but focused on sportiness. Sport, Sport Plus, Advance and Advance Plus are all somewhere in the middle