Now, I going to do a writeup like if the car was BONE stock. But if you could afford the proper AEM or K&N you can't go wrong with that.
Total cost: around $600 with filter. Again this is DYI.
1) Remove all Stock air ducting and airbox. Carefully Remove the Air flow Sensor from the box. You are left with a 2 1/2" original kinda flex hose that goes to the throttlebody. That stays
2) Take apart the airbox, if you look inside the top half you will see a 2 1/2" plastic pipe molded into the top half of the air box.
3)Take a Dremil or cutaway tool and carefully cut away the 2 1/2" pipe from the airbox. Note this pipe also has the attachment for the air flow sensor. Do not touch that.
4) You should now have a 2 1/2" pipe with the airflow sensor attachment. Now you have a choice of using 2 1/2" bore for the entire cold air or go up to 3" because its easier to get a 3" Filter and for better flow.
5) We decided to go with the 3" option so bought a 2 1/2 to 3" increaser hose and 2 pieces of small pieces of 3" aluminum pipe. Next bought 3" flexihose about 2' and a K&N Extreme Filter.
6)There is a 3" hole next to the radiator overflow bottle. Relocate the radiator overflow bottle to get access to the hole by turning around the bracket using the 10mm bolts.
7) Ok time to assemble. Attach your plastic 2 1/2" plastic pipe(with airflow) and run it to your increaser, then to 1 3" aluminum piece then to the 3" flexihose down into the hole to the other 3" aluminum piece to your K&N filter. You K&N filter is now away from the hot air and in the left front bumper.
8 ) Next thing is to make a water trap so water does not enter the engine. You can take one of the 3" aluminum pieces and tap off a water trap so water goes in that not your throttle body.
9) Do not DRIVE THROUGH FLOOD. Cold air or not it will friggup our tranny/ gearboxes and your cold air will make it worse. PARK UP AND WAIT!!!.
10) DONE. you will get a feelable different on mid to high end torque and HP.