Here is a Cabin Air Filter DIY for a 2006-2012 Lexus IS (250 and 350)

Works For:
2006 Lexus IS 250
2007 Lexus IS 250
2008 Lexus IS 250
2009 Lexus IS 250
2010 Lexus IS 250
2011 Lexus IS 250
2012 Lexus IS 250
2006 Lexus IS 350
2007 Lexus IS 350
2008 Lexus IS 350
2009 Lexus IS 350
2010 Lexus IS 350
2011 Lexus IS 350
2012 Lexus IS 350

Source: innocuous_name