Sprokets

Im looking to change the sprokets on my bike to make it wheelie easier.  I was thinking of doing -1 +2.  I would like feedback on this, how bad does it affect the top end speed and the speedometer?  Also where can i buy the sprokets?  Thanks!!

its always a trade off.   -1,+2 is pretty common.  I rode with that combo for a season and I really liked the bottom end grunt you get from it. You can still ride it hard without the front coming up super easy, but if you crank on it, it will come up.  You will lose some top end speed, but some poeple dont care, its not often that your going to miss the fact that now you can only do like 140 instead of a 160.   something else is that you will need to pick up a speedo healer if your concerned about having an accurate speedo.
 
you can check out superbikestore.net, I think they have free shipping on sprocket/chain combo's

I am running this combo right now and I love it. (Exactly what Krash said).

520 conversions are nice.

a 520 is not a gearing change.   520 referrers to the size of the chain, people do commonly go from the stock 525 to a 520 when also changing the number of sprocket teeth.    They are two different things that people often do at the same time.  

what is the benefit of going to a 520 chain over the stock 525?

Also what are the stock teeth numbers for the front and back?

16 front and 46 rear.  so to do the conversion you need 15/48.  Doing the 520 conversion saves some weight because the chain isnt as thick.  ppl say they do wear faster tho so it is a trade off.

To me the -1 +2 is the best upgrade to any bike.  Makes whoolies so much easier to pull up and there is a lot more engine braking which is nice when learning, I love this combo and it is the first thing I do to all my bikes.  

Just did this about a week ago, and its great my gas is burning up a little quicker but small price to pay for the all around power.

I was thinking of this.
I can power my f4i up in third though, so i'm not sure how much i need it...
What's it do the the gas mileage?

well, it really is all relative.  Your bike doesnt have any more power, its just moved down in the rpm range, so it feels like it has more power.  example, coming out of a corner at 8-10k rpm feels very strong with the sprocket change, to get that same feeling with stock gearing you need to be closer to 12k.
same power, just the gear ratio is changed so you have to up the rpm's bit with stock.
 
On the flip side, with stock gearing on the interstate, running 80mph, you may be at 7-8k (my numbers may be off - just using as a reference).  but if your gearing is down, then to run 80mph, you may need to be 9-10k rpm.  So, since you are running more rpms, you are also using a little bit more gas.   
 
also, if you dont correct your speedo, your odometer and speedo will be off.  bike will register that you have gone 120miles, when you really only went maybe 110, addind to the feeling that your gas mileage is out of whack.