Ram air will only add maybe 5hp, and thats when your driving pretty fast. You can get it aftermarket, but it is not the most cost effective mod for the car. A cold air intake will net you about the same hp gain for less $ than the Ram Air. #1 mod on your list should be a lid anyways. They're about $100 brand new and you will feel a difference in throttle response.
Not trying to advertise, but you should definitely sign up on LS1tech.com. A huge group of guys who for the most part know their shit.
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