Welcome to the site Reggie
Nice to have you join us.
I have not used a PC, I just have Beowulf Titanium race cans with the baffles left in and a K&N filter in the standard airbox.
This has cured the 5k flat spot, (where it goes weak for the drive by EEC noise tests), and it pulls better in the mid range. Sounds great as well but a bit noisey even with the baffles in!
Economy is no worse than before when all was standard, i.e. usually averages around 40 mpg or sometimes a bit more on normal "fun rides", (I am a bit calmer these days as I am an old git). If you push it hard it will go down into the 30s, but the main thing with the Falco is that you don't need to thrash it to the limiter to have fun. You can keep the revs down to 6k or a bit more and quick shift through the box using the torque, if you are on long runs/commutes, and the mpg will go higher. I have managed 50 mpg on a long relaxed, but not slow run.
Can't say much about commuting in serious traffic, as I have never done that with the Falco, really heavy traffic could obviously bring the mpg down significantly.
Don't think the PC III will change things much unless you hammer it, but as you say the pleasure will be worth it!
Changing the front sprocket for a 15 tooth, (to gear it down), will make it more flexible and easier to use in traffic and allow you to use 6th gear more on a long commute. (see other threads).
Enjoy the bike, you made a great choice.