Fastest Stock 03' cobra run on street tires is a 12.42@113 or 114. By the driver who got the 12.9 run for a stock z28. One the name hits me I will post it. And hell motortrend got a 12.8 also. And sometimes they are not known to have the best times. Alot of mags have then in the high 12's. And i have seen several run 12.80's stock and one run a 12.75 on street tires. The IRS is tricky to launch but is still doable. Granted there are the usual 13.0's.