Dude a full on air induction kit does give you a power gain of abot 1kw, not that much but its still a gain. and yes you will get the sound out of it. However if you want more of a power gain just finish off a stage one conversion, once you got the induction kit get the exhaust replaced with a free flow (without the catalytic converter) and then get your onboard computer remaped. Once you done those simple mods you will have completed a stage one conversion and can gain anywhere between 11-14kw.
but yes a cold air induction kit is worth getting. Small power gain and reaches the revs a bit quicker!
peace
like above, for a decent mod get a panel.
i had a 1.4 with a simota carbon filter on it. it was a closed system and sounded really good.
cost about £90 of ebay new.
i wouldnt go spending any more than that tbh.
a ph 1 airbox is a good mod, but im not sure how youd get a pipe to it from your throttle body. which is rear mounted iirc.