There's a whole lotta growlin goin' on! Sorry couldn't help myself. I noticed two things here.
Save money and buy a K&N filter and replace the original filter. Make as many modifications to the air box to make it work better or go the route of the air raid ( three times the money of a K& N drop in) and get quick throttle reponseand growl you didn't notice in low gear. Put in crane wires and great plugs and have very little idle problems(No shake) Then road test it. Start at a stop and push the peddle down 3/4 of the way have quick GROWLING pick up to 20 mph. Push the peddle to the floor and have another pick up at 30 to 40. The pick up is quick and the car feels like a stronger car.
Leave it as a factory car with no change in air filter or don't change the factory wires or put good plugs in it (Leave it stock) and have a car that idles rough and sorry pick up. Just my opinion and many others here!
The second thing is go the name brand route with the air intake stuff and not the knock offs. There are those who make their own systems but how good are they?

__________________
Cool Vanilla white 2007 Pt. Cruiser, Airraid system, Crane firewires w/Champion D plats plugs ...what's next?
It's not just a matter of MPG... it's the ride! Still wish it was better!