It seems that the stations are trying to make it appear that they are not a Pemex dealer. Some have simply put up new signage with a catchy name. Not associated woith any USA companies and still selling the same Pemex fuel. Others claim to have some super additive that allows you to get more km's from a tankfull. One chain of about 4 stations offers to test the pump before filling your tank. They have those stainless containers with markings. Real scientific looking. They pump 2 litres and show you the level. If it is ok they pour it into your tank. I tried it once just for laughs. It was slightly over the 2 litre mark. The most innovative painted everything pink part of the name is "chica". No they do not have attendants in bikinis but they are all women! Chevron is just a name but they add Techron to the tanker. I predict that compamies like Arco will push Pemex out of the retail business. BTW: There is at least one oil company in Mexico selling DEF fluid. They even have it those big 1000 litre containers. So the ULSD must be just around the corner.
Moisheh