Each time I've downloaded the product it contained the R&A as well as the Data Collection portion and you select which part you're installing from the initial splash screen.
In the Data Collection portion you add the snap-in's from the initial install or afterwards by adding a new patch or using the applet in the control panel to add/remove portions of the software.
In the R&A portion I believe you add / remove the same way so that you can add in a license for items you have an select the new standards, policies either by upgrade or through the add/remove applet in the control pannel