If you wanna go pro environment then you need to go for 50ppm
In layman's terms you can regard sulphur in diesel just like lead in petrol, except that lead is added and sulphur is part of the process in crude oil.
So from a performance point of view you can boost a 500ppm running engine a bit more than a 50ppm running engine and the exaust gasses stink a bit more like Sulfid but thats all.
:=):