I bought these BFGoodrich Rival tires for use as Autocross only on an NB miata using 8 wheels. The 205/50R15 size has a slight stretch on this size wheel, making for a stiffer sidewall at lower pressures for better turn in response. I have a limited number of miles on the Rival since it is not driven at all on the street, but have competed in 6 full Autocross events on the tire(6-9 runs/event at an average of 60seconds/run).
The Rival is stiff, but compliant over bumps and does not give a harsh ride. Wear is exceptionally good. When paired with the proper amount of camber, and heat cycled correctly, there is no chunking of the tread blocks it it wears very smoothly and slowly. The Rival is plenty noisy, when cornering, but relatively quiet when traveling in a straight line. This noise is necessary for helping determine the grip available mid-corner.
Turn in is immediate, the low and wide treadblocks reduce tread squirm and the sidewalls are stiff. Traction is very good, and has a very smooth and predictable break-away. The Rival has helped improve my straight line braking ability and trail-braking as well.
As a final comparison, I had been competing in the STR class at my local Autocrosses and finishing regularly between 5th and 10th place overall on a summer tire. On the BFGoodrich GForce Rival, I have been consistently part of the top 3. The Rival is just that good. And it will be even better when paired with a properly stiff suspension.