In my Honda City Ivtec, I am using K&N Stock Replacement Air Filter since April 2014. It has been 1.5 years now, the car with K&N filter drives marginally better than the OEM
/Regular Air Filter. The K&N is required to be cleaned every 10-12K kms and it costed me Rs. 5290/-
Coming to the Free Flow Exhaust, My car has the NITTO FFE that was fixed by Autopsyche Gurgaon. It is just having the end-can and muffler unit because I was not inclined to get a fully modified exhaust for my car. I needed a deep exhaust note for my car. The cost of Exhaust was 8K. Till date there are no issues with car's performance due to it. Below is a small video of my car's exhaust.