I just picked this car up and have a question about the brakes. I've got the 15" rims, and I know that there were two front brake sizes offered for this car. If I have the smaller setup, can I upgrade to the larger size without going to bigger rims, or is this why they had two options?

This is our first try with a Volvo since our 2000 S40 disaster, and I'm hoping for much better results.