You say the K&N possibly but you think it looks cheap... how often are you going to be admiring it? If you are more in to underbonnet detailing & want some sound then you probably want something with a bit more metal/shiny bits (Powertec ??)

If you want sound & performance, then a green or K&N I would say. I had a PiperX foam cone on my MG which ounded lurvely, but that was a V6.

If you want outright performance, then generally you are looking at an enclosed induction kit but you will lose sound with that. I've got an enclosed Piper Viper kit on the Elise and notice zero difference in sound. Still looks nice with the Carbon Fibre cover.

By the way, my K&N was £69 plus delivery (£6 or something). Very happy with the sound and seems to be a bit sharper on the throttle. Flexi arrives on Monday !!

Andy