Yes the air filtration is much better using the hpi baja filter. One of the biggest things to get the inner filter sealed is putting a thin layer of synthetic grease on the base of the inner filter so when it is slid on the filter housing it seals at the base. Then put an outerwares on the outside. Also I use an angled shred stack from ddm racing to tilt the filter housing up a little bit for ease of accessDoes HPI air filter kit instead of the stock redcat one really improve something??