Cold Air Intake comparisons??

I have a 97 Jetta w/a 2.0L. I would like to add a cold air intake. First, I have noticed that depending upon manufacturer the prices vary alot. From around $48 (Vibrant and Toucan/Ractive)for what looks like a replacement for the filter box and a new filter, to $155 (Neuspeed) for a new filter, box, and some ducting and last was Injens for about $255 (Injen) for what looks like every thing past the MAF. I could care less about who makes it, I just want to know why the huge price differences? Am I just paying for a name?? Or are the prices related to what is in the kit and you get what you pay for type of thing?
Second, If I increase air intake do I need to upgrade the MAF with bigger, Header, and back to the cat?. (I already have a Pace setter/Monza cat back exhaust I have not yet installed).
Third, I can't seem to find any bigger MAF or after market headers if I do need to upgrade.

ok with a 2.0 you wont get to much more power. A lot of us do this, sand down the airbox so its all nice and smoth insted of all the bumps and stuff then just put in a drop in K&N airfilter. this works just as well as any other air intake.

Thanks. I did that this weekend. It seems to work pretty well.