Please check the following link to better understand how K&N and other performance filters really work :
Air Filtration Test
If you are doing other modifications like free flow exhaust and plan on using your car on the track,there are no benefits.Instead just clean the stock filter every 500kms and replace it every 5000kms.Remember to change the oils and other fluids every 5000kms as well and your car will perform better.
Ps:I am using a free flow exhaust with the stock filter and it works great.With K&N or other such filters your car will sound great it will perform a little better too, but for the price and the kind of damage it does to your car in the long run it is not recommended.