What changes have you noticed by changing the stock air filter out to a K&N? Any HP increase? Any throttle response increase? Is it worth it? I have a 1999 1.6L LX...

 

have you used the search feature on this forum? It's the rightmost item of the menu bar on top. There has already been thorough discussions on the K&N drop-in. do a search and find out

and welcome to the forum

 

Save the money for a short ram or CAI. The drop in is still severely limited by the air box.