while running the risk of getting into it with Rocket666 again like on the T-Tuner midpipe discussion, I will give my two cents.
First of all, an air filter change should not require a PC3, BUT any bike can get benefits out of one, especially with a proper tune. My understanding is that these bikes come a little bit rich right out of the box, so adding more air with a filter should actually bring them closer to that 14.7 a/f ratio that is desired for best power, but there are no gaurantees until you actually check it. As for needing bigger injectors, that is not the case at all. Your current fuel system should be sufficient to support up to 140 hp with proper tuning. Beyond that, you will need a bigger pump and injectors (or just buy a fricken R1). For those not in agreement here, I ask, how the hell do you explain bikes running 30 shots of nitrous on the stock fuel system and not blowing? There is a lot to be had in proper tuning...and if you want to go really wild, get the YEC kit ecu for the ability to change fuel, ignition timing, and redline.
So, i would suggest something simple as a first attempt, turn up the idle a little bit. While the computer should take care of it, again, there are no gaurantees. Seriously though, if all you did was the filter and not a slip on, you should be fine. I do not recommend letting your bike idle for long periods of time either, so I guess rocket and I agree there. If you do plan future mods though, I would suggest a PC3 or the new Bazzazz tuner, or even the Factory Pro Teka SFI. I hear really good things about that one.