I have Honda Stunner CBF 125 2009 model. I just need to know is it possible to replace the typical air filter with mashroomhead air filter to improve the bike performance?
Is there any other way that I can use to improve my bike performance?
You have a carburetor on that bike. You may need to do some adjustments, if not, you will make the air fuel ratio leaner and that will be really hard on your exhaust valves.
The more oxygen you have in your air fuel ratio beyond 14.1:1 will increase your combustion temperature. This, in turn, can damage your exhaust valves due to too much heat.
Consider getting a jet kit so you can increase your main jet size and drop your needle into your slide to get the optimum AFR.
You can refer to this article for further information about AFR and carburetors on motorcycles
This is a response to free flow exhausts creating a lean condition that may be beneficial to your knowledge base.
And finally a response regarding identifying lean or rich conditions on a motorcycle.
Best of luck. Consider the jet kit along with a free flow air filter.