sorry if repost...
in this drag sim you can race 05+ gt against the 03/04cobra.
http://www.speedshoppro.com/freegateway.htm
the sim puts the cobra at 12.6 in the 1/4. couple of things to note tho.
1) model assumes perfect launch and shifts (ie, very skilled driver).
and 2) the chasis dyno used to model the cobra was close to 400 rwhp. they are (under)rated at 390 to the crank, but I'm not sure if they are THAT under-rated (maybe dan04 can confirm). so the model might predict a tad faster than another stock cobra.
btw, you need Excel 2003 or the sim won't work.
geoff