A drop in is just an aftermarket filter that replaces your stock one in the air box. It just... well... drops in...
With that setup, you will definately need a jet kit. Some people do "discount" jet kits, which basically is just a different main jet and then they add a washer or two under the stock needles. This may sound like mumbo jumbo if you have never taken motorcycle carbs apart, so check out this thread.
http://www.fzrarchives.com/fzr/forum/index.php?act=ST&f=25&t=8141&
It gives you a little bit of an idea about what motorcycle carbs are like. It was something I did a long time ago and now know a lot more about, so if you have questions give a shout out.
But anyways, I suggest going with a Factory Pro Jet kit over the Dyno Jet kits, or the discount ones. I like the simplicity of the Factory Pro kits over the Dyno Jet ones (no drilling of the slides), and the discont ones are just masking up your lean condition, instead of fixing it. This is just my opinion. Some may disagree.
A stage one kit will be all you need for a drop in and full exhaust. It will consist of a stock pilot jet (#32.5), new adjustable needles, a 110 "small round" main jet, and then some adjustments to your float height, and idle mixture screw wettings. This is stuff you can do yourself if you feel your are mechanically inclined. If if makes you nervous to do it yourself, then I suggest taking it in, but it will run you a crap ton of money (something in the $250-350 range to have it done ($65/hour labor costs add up quick)). With that setup, you should be pulling around 75 horsepower to the rear wheel. Not bad for a bike that came with that much at the crank.
With my stage 3 setup Im pulling 80.2 whorespower at the rear wheel. But its a tning nigtmare. Every little bit of change in the weather makes the bike run a little funky.