Hi I'm 16 and I own a 2005 Infiniti g35 coupe with a gismo exhaust system with cats removed. Since i have been earning some extra money i want to find a quality cold air intake to add a little horsepower. As of right now my car gets 315 to the wheels. any reviews or suggestions would help a lot!

Nismo*

2005 with just a Nismo exhaust (cats or not) should not be getting 315 to the wheels. The 298hp G35 w/6mt should put around 253whp assuming 15% driveline loss. Auto would be about 20% loss. Assuming 6mt then your 315whp number means removing the cats and putting a slightly less restrictive exhaust netted you 62whp. No way. If you have the base 280hp version then it's even worse.

Personally I like R2C intakes but Stillen, Injen and others make numerous short/long tube variations.

Yeah, like Aud said, no way are you getting 315 HP at the wheels.
I have a 2008 G37 Coupe, Auto. It is 330 HP at the engine, (about 270 HP at the wheels) stock.
I've got the Stillen Gen 3 Cold Air Intake, Stillen High flow CATS and ARK GRiP Cat back exhaust.
Also spent $600 for an UpRev Dyno tune at Z1 Motorsports.
I am now getting about 305 HP at the wheels.

I do really like the Stillen Gen 3 Cold Air Intake. It was my first mod, and produced a nice sound with a bit more power.
But, you won't get all the power possible, unless you get a Dyno tune.

^^^ going to Dragon this year?

So you guys are saying once CAI is added, tuning is required to get the maximum hp out of it? What do i/we need to look at as far as tuning?

NO tuning required with intake. Once you begin to add, HFC's, exhaust and intake, yes you better get a tune....

What about carbon fiber? Had a carbonio CAI on a 1.8t jetta some years back and loved it. Carbon fiber is light as unicorn hair and as strong as my girlfriend's breath in the morning and doesn't conduct heat well at all so it kept air temperature relatively "cold" throughout entire pipe. I'm on my first ever g35x, but I'd assume carbon fiber would have the same characteristics across the board.