What nefarious reason do the US HLS cops need these?

[NorthernRaider]

They like good oil and regular filter changes oil, air and fuel ( how can you tell I worked in a dealership) make sure the oil filters have integral bypass valves as cheap knock off filters dont have them, this will kill your engine. On mine as I did with ther Transit was to rip out 90% of the Emissions plumbing and wiring and it ran much better.

Oh the front calibre brake pad pins can sieze up and the piston dust covers split its always worth changing them if you buy one, takes about half and hour to do.