If you like them so much (as in they give you so much performance), why not experiment with them (with ballast) to see if you are better off with them in your current class?
For me that would mean adding about 230 lbs of ballast. Plus the contingency offered by Hoosier or BFG makes that a hard switch to make. I recently tried out some Yoko take offs back to back with some Hoosier R6's and those gave me about 1 to 2 seconds per lap. Both of them were take offs. The Yokos were definitely a softer compound though they wore through much faster but they didn't seem to drop off as much as the Hoosiers did when driven hard.