I hate to bring the thread back from the dead but I HATE these tires.
I run them on my Evo, and while they have great feedback they do NOT have a high cornering grip. Keep in mind this Evo has Ohlins coilovers, sway bars and other suspension goodies and I've spent countless days tweaking things. They squeal very quickly way before you would think so.
What tire did you run before? I am running the Rivals on a highly modded SVO (444rwhp, '03 IRS, etc) and a Audi RS-4. These tires corner better than any other street-able tire I have tried in years on a dry track (Advan AD08, Ecsta XS, Ventus RS-3, Direzza I/II, Pilot Super Sports, Conti DW, Azenis RT-615K, etc) and feedback has been excellent.
They need a couple of laps to heat up and I run mine about 2lbs higher than Advan AD08 and Direzza II. They tend to squeal a little on the first couple of laps but settle down afterwards. I also noticed they needed a few heat cycles and about 500 miles of scrubbing to really come into their own.
That said I think the Direzza II is a better tire in the wet and I have a set of Potenza RE11-A coming for the SVO shortly as I am more concerned about a balance between dry and wet handling on that car since it is also a DD.
However, I know once the 275/35/18s Rivals are released in July that they are going on the Cobra for warm weather events.