How do stat limits work?

I had interpreted it as the maximum you can increase your base stat to, but my group is convinced that there is nothing that can buff you past them either. So if I'm playing an Iosan storm sorcerer, and I put an extra point into SPD, I'll have a SPD of 8 and a Hero SPD limit of 8. Can I then cast Fair Winds and improve my SPD to 9 for the round, or is that in violation of the stat limit?