I use style 209 rims. Here is a link to them below :

BMW wheel style 209 | BmwStyleWheels.com

Would I be able to use say 25mm or 30mm spacers all around to fit the tires on them? I mainly bought them because I wanted a smoother ride so I purchased something with a taller side wall.

Is there a downside to using spacers that are 25mm or 30mm all around?