Air filter

[ryan17hurley]

Currently on my car, ive done no enigine mods, i want to keep the enigine bay looking more less standard due to parents, but am after more of a sporty sound, i dont want spend much more than £25 on this but been told an air filter will help give me the sporty noise i am after, the ploblem is i dont know the diamter of my existing one , how can i find this out, if any help its a clio 1.2 . 01-05 spec

thanks