HGG Community Forums

Perfect foundation are 100% breeding ability and c papered, and Exeptionally perfect are 105% breeding ability and b papered. Giving a 5% boost to a PF will make them same as Exeptional breeding ability and B papered. I did a search and 1% breeding boost on PF mares made red papered, so even a 1% boost seems to make the next paper grade.
I'd say it's worth it if you can't get an Exeptional breeder in the same color, or if you GMT'd it, otherwise I think I'd look for an Exeptional Producer or Exeptionally perfect in that color.
Exeptional breeders with a 5% boost make A papered, I found in my search.

Yup, even a 1% will get him to B. Then it just depends how high of a B you want, vs how much you can spend. :)