For ease of installation, and a great sound, the Xcharger. But you won't have a dyno sheet to give you bragging rights.
Vortech and Procharger both make a centrifugal for the 4.0. You get a little more power but not the low end torque of the Xcharger. The centri will run the Xcharger car down in the 1/4 mile once it gets rolling.
The ebay turbo "kit" is just a box of parts. And not even all the parts you need. That is the cold side only, you still have to fabricate the hot side, and figure out how to make the cold side parts they send fit your car. You will need to figure out what injectors you need, and how to plumb the oil lines.
2013 MCA Convertible, automatic - Revelare Designs cowl hood, Hellion single turbo.