C. Bolt-Ons
Bolt ons are any part that assists in the making of power, that does not touch oil. It is common knowledge that they are the starting point in modding your car, so the fact that you should complete your bolt-ons should go without saying. Let's look at some of them and what they do.
Lid:
A lid replaces your stock lid, which was designed with comfort, not power, in mind. Simply put, an aftermarket lid does not have the restrictive air silencing fins and baffle found on the stocker. It allows more air in, and is a "must do first or second" mod. A lid is a lid, don't ask which one is best.
Cold Air (Ram Air):
The factory placement of the lid is poor for two reasons: the amount of space that air has to get into the lid is minimal; and placing it right on top of the radiator all but insures that you will have hot air entering your motor. A cold air (or ram air) kit fixes both of these problems. Either drawing cool air from under the car, or sealing your factory ram air to the cool outside air. Both methods ensure that enough air is getting in, and that the air that gets in is not hot.
Headers:
Headers replace your stock exhaust manifolds. They assist in the evacuation of spent gasses from your heads. They do this two ways: 1. first, they are free-flowing, which is to say they do not restrict exhaust flow in the slightest. 2. being free-flowing is not enough - GOOD header designs take it one step further by creating something know as the "scavenging effect"; that is, the flow of one header primary as it travels to the collector, creates a void or vacuum in the other primaries, effectively sucking out the exhaust as it is released from the head. I have always preferred "steeped" headers, for this very reason. Steeped header primaries get larger as you move away from the head's exhaust port. This greatly increases the scavenging effect, and increases your power potential.
Underdrive Pulleys:
Most commonly the crank pulley; it is simply a smaller pulley. 1. The rotational mass of the pulley is less, and therefore lighter and easier for your motor to turn. 2. It effectively reduces the amount of power required to turn the rest of the accessories, much like shifting to a lower gear.
Electric Water Pump:
Following hand in hand with the underdrive pulley, the electric waterpump gives the motor one less accessory it has to turn, thereby freeing up a few more HP. Although there is debate as to how much, no-one (who isn't a moron) disputes that it does free up at least SOME amount of HP.
Manual Rack-And-Pinion Steering:
Along the same lines, the MRAPS gets rid of yet another accessory, thereby freeing up power. It also weighs considerably less then the stock power steering system.
Exhaust Systems:
While there is A LOT of bullshit that flies around the Internet about "this exhaust sounds better then that one", this post is not for posers who want to whine about rasp. The very best-flowing exhaust there is, is a true dual X-pipe or H-pipe setup, with or without bullet mufflers. The next best thing is a cutout in the I-pipe. No cat-back out-flows a cutout; no Y-pipe setup out-flows true duals. Period.
Intake and Throttle Body:
I put these together because much like heads and cam, they should be matched. Again all bullshit aside, the best is the LSX 90mm intake and a 90mm throttle body. They are very expensive. A cost-effective second place is the LS6 intake and a ported stock TB. Either of these two choices are worth it, and have been dyno-proven time and again.
