jginnane

Cabin air filter replacement installations are an extra $100-150 + the part ($30) when included with the "B" service on 3rd generation Acura TLs (via acurazine.com)

Instead, I spent half an hour researching the DIY pix, and 10 minutes doing the actual install. Used a Bosch activated-charcoal filter that cost $18, though I could have gone cheaper with a paper one for $10.

The process is the same as described in this thread for the Z. You simply need to drop the glove box door, which involves unscrewing a few screws and popping the plastic a little. Pull out the old filter and put in the new. Then bolt her back up!

Both Honda/Acura and Nissan rely on most owners' desire not to break something in the dash, which is why they're able to get away with the $150+ for a "professional" install.

Now, from my experience with 3rd and 4th generation TLs, and the 09 370Z: Do you actually need a cabin air filter? Or ... do you need to replace it every 25K?

In most parts of the country, the answer is "no!" If you live in dusty areas and your windows are up all the time with the a/c blasting, then it might be a good idea. (Think: AZ) But in the middle climates, it's essentially a useless add-on. Plenty of dirt and dust will come into the car through the doors and windows anyways.

Yes, a cabin air filter will collect dust (and possibly leaves) if installed. If it's not there, the dust will blow through the duct system into the car. If a leaf manages to get in, it will sound like a baseball card-in-the-bike-spokes as it rubs against the fan blower blades, until it breaks up.

But the amount of air that gets sucked in from the top of your hood for the a/c system is a lot less than you take in through your two engine air filters. If those filters aren't reeking filthy at 10,000 miles, you are better off not worrying about cabin air.