I have a set of FR-S wheels for my winter tires. The wheels have a Subaru offset so you have to use spacers. I used a set of 20mm spacers and they fit perfectly. They have new studs because of the width of them. Here is a pic of the spacers. 5x100mm billet aluminum with a 54.1 hub centric bore.
I bought these hub centric rings because the FR-S/BRZ wheels have a center bore size of 56.1mm. These fill the gap for the 54.1mm Toyota hub size.
This is the back of the FR-S/BRZ wheels. You can see the holes where the studs will fit into if you use a 15mm or 20mm spacer. If you use a 25mm spacer the thickness of the spacer is more than your OEM wheel studs so they won't stick out past the spacer. No worries with the FR-S wheels though. You can see how the centering ring fits inside the wheels hub. It just snaps in.
This is how they fit with 20mm spacers. Perfect!