the power differences aren't that much..you'll get about 1-2 more whp from a cold-air. you'll lose some initial torque..but make it up plus a bit more on the higher end.
there are pros and cons to both though:CAI
: more power, hydrolock, filter gets dirty fasterSRI
: less power, virtually no hydrolock, filter stays clean longer
if you're adding a nitrous shot..i would just stick with your shortram instead of wasting money on a CAI
. you'll get the exact same power with nitrous whether you have CAI
will only be more powerful when your not running nitrous (about 99.9% of the time).