Re: Here\'s one...
A non run-flat tire should improve ride, straightline traction, and handling as well. Because of the more rigid structure, a runflat is heavier. And this means more unsprung weight. Dodge claims that the Competition Coupe is lighter at each corner by about 20 lbs, with the swap to Hoosier racing slicks and the BBS wheels. How much of this is down to the tires, I don't know. But GM cites a weight savings of about 4 lbs at each corner for the Z06, compared to the runflat-equipped standard 'Vette.
C&D tested standard Corvettes on stock runflats and then swapped them out for the Z06's tires. They selected the twistiest sections of DaimlerChrysler's proving grounds and got these results (among others):
Base C5, stock tires
Autocross course, seconds: 59.0
Racecourse segment: 54.3
Base C5, Z06 tires
Autocross course: 57.4
Racecourse segment: 51.4
With the Z06 tires, it picked up 3.56 mph average on the slalom and 2.0 mph in the emergency lane change maneuver. The MSRC-equipped C5 on touring mode picked up .06g on the skidpad due to the tires alone.
You can read more of that test here:
http://www.caranddriver.com/article.asp?section_id=4&article_id=7004&page_number=1