guys, seriously now, a "non-happy dyno" on a stock car will go anywhere from 120-140rwkw depending on the health of the car and other factors. as al said too, you're mechanic is probably saying that to you to squeeze $$ out of you. oh dude your car is really low on power you need this this and this now to make it go hard.
first things first. get an exhaust, a cai, and maybe a hi-flow cat. you will notice a very nice gain alone just with those mods.