While I do know a fair bit about suspension systems that's hardly the point here. If you're going to change the characteristics of a suspension by pressing a switch on the console there has to be a connection to some suspension component. The only such connection in an X3 is to the struts on a DHP equipped car. Perhaps you believe in magic too
And by the way I do own an X35i with SAP and DHP, and driven SAP only cars multiple times. While going to sport mode on an SAP car does change throttle response and transmission behavior I don't feel any difference is suspension stiffness which why I added DHP to mine.