Air Filter I installed a cold air intake K&N filter. On one of my first 9000's, this was the first upgrade that I had made to the car. And, ironically, it was also one of the last changes I made to the car before it went to a new owner.     A number of people asked me what I have done with my air filter. The following pictures were taken along the way and upon completion. First, was to remove the stock air snail from the fender. I kept the stock air intake piping through to the fender. This ensures that I am drawing cold air from outside the engine bay. I took a couple pieces of PVC piping and extended the intake tube far enough out so that the K&N filter would have enough room to clamp down on it. I used some duct tape to enlarge the outer opening for a good clamp area. The inner diameter of the PVC pipe remains the same as the rest of the stock pipe except for a slight venturie point inside the PVC addition.   Click to enlarge       Here you can see the filter installed in the wheel fender outside of the hot engine bay.   Click to enlarge       Not being completely satisfied with my home grown air filter set-up, I bought one of the open air filter kits from Engstrom Motorsports. This piece provided a cleaner set-up and the inner diameter of the intake tube was larger than the piece that I had made out of PVC. However, I opted not to go with the JR filter that it came with given that this filter was smaller that the K&N that I had already installed. So, I stuck with the K&N filter which had roughly the same mouth diameter. I installed some duct tape around the openings to ensure a snug fit.   Click to enlarge