Re: High rpm
Oh and for the other things mentioned, get yourself a full service (oil change, 8 new spark plugs, oil filter etc etc). It could be something or nothing. Also as said above, get your belts done aswel - mines actually in the garage now getting the cam variator and belts done as we speak (get it back thurs all being well)!
When I got my car it had a K&N induction kit fitted on it aswel, it made alot of noise and didnt make much difference to the power.
I got a proper airbox from someone on ebay who was breaking a 2.0 145, it cost me about £35 I think.
When fitting it...you NEED TO put it in from the floor up - i.e. take the wheel off, take the plastic inner arch out and push it up that way, it WONT fit from the top down, believe me I tried for a while before I thought to my self "there must be an easier way"!
Hope this helps...