Depends on what rear tires you are running, 5-speed or manual, and suspension setup.
Street tires should be around the low to mid-13's with a good launch.
Drag radials should be mid to high 12's.
Auto with a shift kit/stall will be the better times above^
5-speed will be a tad slower unless you are an EXCELLENT driver.
98' Mustang GT coupe, CAI, trickflow 75mm intake, 3.73 gears, O/R x-pipe, flowmasters, short throw shifter, 24lb injectors. 183k miles
95' Mustang GT vert: AODE, 2.73 gears, O/R xpipe flowtech mufflers , 410,000~ miles. (totaled, sitting in yard)