For the normally aspirated AJ16 4.0s, the emissions package was in two
versions. The “Federal” version used multiple (primary and secondary)
catalysts and four (4) heated oxygen sensors located upstream and downstream
of the dual primary cats. The “Rest of World” version used dual catalysts
but with just twin downstream heated oxygen sensors. The supercharged AJ16
4.0 used the same “Federal” version regardless of where it was sold.
Sounds like bad news for you … if you were wanting to run “high octane
leaded fuel”. Of course, octane boosters could be an answer.