The K&N E-2992 is a round, straight-profile replacement panel filter built on K&N's washable, reusable design rather than a disposable paper element. The media is a layered, oiled cotton design intended to improve airflow and capture contaminants. The buying case against stock is cost over time: you clean and re-oil the element instead of rebuying, and K&N backs it with a No-Hassle Lifetime Limited Warranty. Keep your expectations realistic on performance. The manufacturer says the filter is designed to provide an increase in horsepower, but it does not publish a number for that gain.
Fitment is where buyers should slow down. Published references do not fully agree on engines and years. The manufacturer's own E-2992 page is titled for the 2.2L diesel E220 CDI, while other references extend coverage to E200, E270, E280, E320, and S320 models, and some tie the part to diesel CDI engines. Confirm your VIN against the manufacturer's fitment lookup before ordering. Long-tail searches for this part usually include "W211 E320 CDI cotton gauze drop-in air filter," "K&N E-2992 vs stock air filter," and "reusable Mercedes E-Class air filter 2002-2006."
No. The manufacturer states that K&N air filters are pre-oiled and ready to drop into the factory air box.
The manufacturer recommends its Filter Recharger service kit, part number 99-5050 or 99-5000, to clean and re-oil the element.
The manufacturer's E-2992 page is titled for the 2.2L diesel E220 CDI. Other references list E200, E220, E270, E280, E320, and S320 applications across 2002 to 2006, so confirm your exact year, engine, and body style against the manufacturer's fitment lookup before buying.
This is a drop-in swap with no tuning required. The manufacturer's install sheet for this part number has you remove the factory filter, slide the K&N onto the intake flange, push the top in until it seats, tighten the clamp to secure the seal, and reinstall the airbox lid. The sheet warns that these steps must be repeated every time the filter is serviced, because an unsealed filter can allow damage to the engine. Check the seal and the lid fit before you start the car.
