If you like how it's working now,keep the stock gearing. It seems to be the best over all.
If you do a lot of highway riding, replace the 16T front with a 17T.
The 17T also corrects the speedo.
If you are keeping the stock gearing, use the factory front drive sprocket & a good steel (best for wear)aftermarket driven(rear).
AFAM sprockets are one of the best.
Even if they are from France.
The AFAM driven sprockets are hard to come by, but the drive(fronts)are everywhere.
A good quality aftermarket driven sprocket is better than the stock one.
Note: Using the non-rubber type drive sprocket will result in a very slight, almost non noticeable, whine from the chain.
The chain I recommend:
DID530VM X' ring at 114 links.
I tried the 112 links,stock gearing. It doesn't work on an 06' without modification to the adjusters.
Way too short.
It also wont work with the 17T front.
As far as where to get them for a good price
I hunted around & everyone is about the same price.
I'm sure someone will chime in with some options for ya.