NEED A TIP ON hP gain PLZZZ

CAI and tuner with a good tune will give you around 20RWHP or about 25 BHP. The nitrous kit will give you around 75 RWHP.

Gears don't give you any power, they just change how the power is delivered...i.e. you accelerate faster with lower gears, but can't theoretically reach as high of a speed and run at higher RPM's on the highway. It's a tradeoff.

best bet for an intake is the Steeda Competition CAI, its alittle more money but its well worth it, also you have to tune the car when you put it on for it to work correctly. id recommend the SCT livewire, it gives you a nice display of gauges and is very user friendly. you will also get free tunes for life =], the nitrous is tricky and very illegal so i would go with a wet shot and look for a zex black out kit, so you couldnt even tell you have it by looking under the hood, and dont exceed 100 shot if your going to run a stock engine block. also i would get a high flow exhaust, i love the magnapacks, its a straight through muffler and it sounds really good, but dont get the cat back bc its a waist of money there is no diff between that and the axle back. all that and if you get 3.73 gears you will not be disappointed i have all that(and pipes O/R xpipe which is very loud and alittle over 100 bucks) minus the nitrous and the 3.73 (which will be added) and im running between 12.5 and 12.7 pretty consistently and thats on my small ass factory wheels with street tires. also used www.americanmuscle.com they give amazing prices, free shipping and no tax i always order from them and im never disappointed!