based on observations from this weekend the Rivals may be the tire to beat. cars/drivers that I consistently outpaxed last year are now on rivals compared to my Z2's and are out paxing me fairly easily.
we also had a test and tune this weekend and I got to do some playing around (with miatas) of stock suspension vs konis/swaybar as well as Z1's vs Z2's.
as tirerack has already proven we found the z2's to be faster ultimately (by .6 seconds on a 45 second course) but they aren't nearly as consistent.
all of my runs with the z1's were within 1-2 tenths of each other, the runs with the z2's were varying by almost a full second, the limits of the z2's are not nearly as feedback filled and easy to find, which caused for some overshooting of the limits and botched runs.
food for thought but for newbs the z1's may actually be the faster tire vs the z2 due to the easier to approach limits. (although the rivals are even faster!)
'03 VW Jetta TDI
'02 Chevy Corvette Z06