why do you want a BOV? DO you have any idea what your getting into or what you want? I suggest you research abit more befor doing anything! Now you have an '03 lancer, so it will still have warranty, and if you put a turbo on this car you will void your warranty, just another thing to think about!
You sound like you just want the sound and not the performance aspect (Turbo) associated with it. I think you're interested in the noise for the wrong reasons...