I think you meant BFG Rival.
The Stock Solo guys are leaving the R-comps for the new high performance street tires and most couldn't be happier. The difference in performance is minor, but their useful life is orders of magnitude greater. I would wager they would achieve Drago's requirement of "1-2 seconds slower and within .5 seconds over 15 heat cycles."
R1 is the tire I have experience with. We ran it in the 25 a few years back and also ran them in the Utah region since they had open tires. I haven't bought an R1 in a while so maybe it was replaced with the Rival that you speak of.... Not sure. I do know the retail on the BFG was over $200.00 so a per lap price is probably no better than the Hoosier.