I love my Injen intake. It's got a decent sound to it but where you really notice it is with your exhaust sound. My borla exhaust before sounded decent but the injen intake makes it sound like pure sex... At least to my ears anyway
I've heard the stillen intake, and my personal opinion is that it is on the quiet side. I have not purchased and installed the lightweight pulley myself, but I have heard good things from those who have.
Obviously you won't feel the difference in your "butt dyno" with the pulley but it will help. The intake, same deal-- somewhat of a performance improvement but you won't feel it. The pro of the intake is you will get more sound from your engine. So I guess that's the most rewarding item here is the sound.
Depends what makes you happy. But a pulley doesn't make noise
I would go to meets and hear a mix of intakes to choose which you prefer. They differ by tone and loudness greatly. Just like exhausts, some a clean, some are throaty. Some are louder, some are quieter.