A "weapon R" air filter is a performance replacment for stock air filters. No car in a factory configuration will have one. If your car is stock, you'll have a panel filter inside the airbox (just behind the battery, says turbo on it if you have one most of the time). This should probably be replaced ever 30-60k, they're reasonably priced ($10-20ish). To replace the air filter, you use use your finger (or a flathead screwdriver). There are 6-8 of these tabs (can't remember how many exactly). Once they are loosem, you can lift up on the top of the airbox and see the filter inside. Pull the old one out, place the new one in the same way and lock the tabs back in place.
