Agreed. I think with the advent of the 321LR, they would be the most likely candidates as opposed to 330s or 350s. Fleet commonality, and common type would be a no brainer for Spirit. As you mentioned DTW being able to reach most of Europe and a nice little build up of BWI going on as well.

Has anyone seen the pics of what looks like a more premium big front seat pair complete with legs rests and power ports in Spirit branding floating around? Definitely looks like long haul, low cost, premium seating. Not trying to start rumors, these could very well just be a manufacturers sales demonstration/mock up for Spirit. But I guess they could be something else.