The Aphache's are the old Mark Knopfler sound, not so much the Sultans.
The Sultans are called that because they are a very clean pickup as I understand, and the Alnico 2 poles make a smoother sound. In the late 70's Mark used a 61 strat and also another strat which was not 100 per cent Fender. The pickups are most similar to the Apache's. The old Mark Knopfler sound wasn't actually completely clean because he used a natural crunch and also he used different set ups from gig to gig and track to track on the two first studio albums.
The sound that Mark used on the Sultans of swing record wasn't very clean at all infact, but as the BK Sultans is a good clean pickup I think Tim named it the Sultans because most people think of the sound of that song as very clean.
The Aphach'e have got the clean Hank Marvin thing of course but also look at how many people have used the early strats for hard rock aswell.
Don't just go on the names, they are just names.
The Sultans with Alnico 2 poles have got a different wire to the 50's and early 60's Strat wire, Mark did move on to SD APS 2 later and these have got the Alnico 2 poles like the BK Sultans but the Sultans have still got a different wire, because the SD APS have got the vintage wire.
