I have been running a drop in after market filter since about 10,000 KMs. I alternate between a K&N and an aFe. Both are cone type and both can be cleaned and re-oiled. I am also running a gutted air intake tube and a 4" hole and flange in the bottom of the stock air box. The truck now has 87,000+ KMs on it.

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2007 Ram 2500 QC 4x4 SLT TRX4-Offroad 6.7L Automatic. '08 Jeep WK 3.0L diesel-wife's DD.
1998 Jeep ZJ 4.0L Automatic Selectrac-project for our son. '98 Jeep XJ-my wife's former DD.
1965 Dodge Polara 880 Convertible 383 Automatic.