if you want 12 sec car, get gts.
from stock gts has lotta pro and cons. but with power FC you will only have pros. and jus on that mod can get you up to 13.7 in quarter mile. and exhaust, Intake
, pulley, 3zz or maybe even blitz s/c will definitly get you up to 12 or maybe less.
gt is quick in stock, but even after the mod its not as fast as gts. take to many of people from this site, many have gone 13 secs with their gts.