Perfectly "stock" 6 speeds are supposed to run high 14's according to Road & Track magazine road tests. Of course these are professional drivers in ideal conditions. Automatics are supposed to do around 15.2.
CAI's have been documented to cut ET's by as much as 4/10's.
My guess is you just need to learn how to launch your car, and practice your shifting.
Power shifting is recommended for best times, but not for drive train longevity.
Installing 225/50/16's on the rear can cut as much as 3/10's just by having less rotating mass.
With an 04, you can disconnect the traction control, and you won't have the pesky computer interfering with wheelspin.
My cars computer has never been tampered with, and the rev limiter doesn't kick in until I hit 6 grand if memory serves. (I'm talking about going thru the gears, not in 6th. gear top end RPM's). I've never tried top ending my car, not a wise thing to do IMO.
Good luck, and have fun at the drags.