Copied from Miata.net post...
[QUOTE=X25;6857138](7) You don't need to remove any bolts on the fog light housing, except one bolt at the bottom (the larger one). Gently push the holding tabs inwards so they let the housing loose, and pull the fog light housing from in front of the car.
(8) Remove the signal light assembly by removing its smaller Philips bolts, and move it onto the new fog light housing.
(9) Install the new fog light housing. I recommend taping the fog light connector to protect it from the elements of the weather.
(10) Cut the hose in half. You can quickly cut it with a blade, but you'll hit the metal line (that gives it flexibility). Cut that with dikes or a similar tool.
(11) Mount the hose onto the fog light housing. I recommend using an 8mm socket and a ratchet to tighten the clamp, since access to the location might be a bit hard with a flat-head.
(12) Cut a hole on the liner. I recommend a little smaller hole than the ducting, so that the hose doesn't move too much. There's an oval line on the liner. I did follow that oval to start cutting a hole. Be careful not to cut any harness behind the liner by mistake; take your time.
(13) Make sure the part of the hose inside the fender liner is not compressed. You don't need much slack inside, and flatter hose will allow faster air output.
(14) IMPORTANT: Turn the wheel away from the car all the way. This is the position that needs the longest hose. You can then cut the hose so that it's almost fully opened at this position. Once the hose is cut and installed onto the new dust cover, turn the wheel hub all the way towards the car and check for any clearance issue.
(15) Torque the wheel hub bolts. Most torque them to 150 lb-ft.
(16) Re-install the caliper, and torque the bolts to about 60 lb-ft.