id say if you run everything the exact same as you did when you ran the 12.5 but with the added mods then ud run a 12.2 or 12.3 but i could be wrong. not likely though
------------------
1995 gt convertible:
3.55 gears, underdrive pulleys, cobra intake , fenderwell cold air, 65mm throttle body, 75mm mass air meter, off-road h pipe, borla cat back, custom diablo chip, 155lph fuel pump lentech aode street terminator w/ 10" converter stalls at 2800 rpms, yokohama a520(drag radials) 275s