Just so you guys know, a K&N air filter may "breathe better" but it also lets in a lot more harmful dust and silica into the engine. I'll never run anything but a high quality paper air filter in my LS430, like an AC-Delco or Purolator.
There is a scientific ISO test of air filters at http://www.duramax-diesel.com/spicer/index.htm where the below chart and text is from. The K&N came in dead last so far as how well it filters the air of harmful dirt.
"In the chart above it’s important to note the different test durations for each filter. The AC Delco filter test ran for 60 minutes before exceeding the restriction limit while the AMSOIL and K&N tests each ran for 20 and 24 minutes respectively before reaching max restriction. In 60 minutes the AC Filter accumulated 574gms of dirt and passed only 0.4gms. After only 24 minutes the K&N had accumulated 221gms of dirt but passed 7.0gms. Compared to the AC, the K&N plugged up nearly 3 times faster, passed 18 times more dirt and captured 37% less dirt."
A K&N is the last air filter I'd run in any vehicle I intended to keep for a while. :)