Objective: Replace the stock header
Car: 2005 RSX-S
Product Installed: JVTR 4-2-1 Stainless Steal Header
Price:$279.99 on JVTRacing.com

Tools Needed:
-Socket  Set (12, 14, and 17mm)
-Swivel Socket
-Extensions
-Ratchet
-Combination wrenches (12, 14, and 17mm)
-Penetrating Lubricant (to loosen tight bolts)
-2 Ton Jack
-Jack Stands (2)
-Mechanics Gloves

1)  

Locate the heat sheild behind the engine

1) Remove the heat shield that covers the exhaust manifold (stock header). If you are viewing the engine bay from the front bumper, the exhaust manifold is at the rear of the engine. (Image 1).
Remove the four 12mm bolts that hold down the heat shield. Now you should see the exhaust manifold (it looks kind of orange) (Image 1a)

1a) 

Remove 12mm bolts

2) Remove the 3 bolts and 2 nuts (all 14mm) that connect the exhaust manifold to the cylinder head

3) At this point, you’ll need to jack up the car and secure it with the jack stands. In our case we were fortunate enough to be able to use JVTR’s lifts (Image 3)

3)  

Jack the car up (in this case we used a lift

4) Once the car is secure, loosen (do not remove) the two 14mm screws that secure the header bracket

5) 

Remove screws at the bottom of the exhaust manifold

5) Remove the 4 screws (2 are 12mm and 2 are 17mm) at the bottom of the exhaust manifold (Image 5)

6)  

Remove the screws from the driver side strut bar

6) Remove the four screws that hold down the driver side strut bar in order to make room for the header to come out. (Image 6)

7) Pull out the header from above the engine (Image 7)

7) 

Pull the header out

8) Install the supplied donut gasket onto the bottom of the JVTR header. Note: The metal gasket should still be on the back of the engine.

9) Install the aftermarket JVTR header in the same fashion as you did the stock exhaust manifold (Image 9)

9)  

Install the header

10) Reconnect the two 14mm nuts and three 14 mm bolts that secure the header to the cylinder head

11) From beneath the car, tighten the two 12mm screws and the two 17mm screws at the base of the header.

12) Ensure that all of the upper and lower bolts are tightened. Also, don’t forget to tighten the previously loosened header bracket screws (Image 12)

12)

Make sure the upper and lower bolts are tightened

13) Reinstall the strut bar.
 
14) Now all you need to do is lower the car, start it up, and let it idle until it is warm.

Congratulations, you’ve just installed your brand new header. Go ahead and take it for a test run!