Hi, regarding the sprocket, I did exactly the same thing, looking for a bit perkier response, and it certainly helped.
I just went out and bought a front sprocket one tooth smaller than standard gearing.
It was only when I took the old one off, that I realized the previous owner had fitted one a tooth bigger than standard to the front!
The difference wasn't that great, to be honest, so I'm glad I didn't know, 'cos I would have only dropped one tooth.
Of course it does affect the rpm for any given speed. (Take the percentage difference of your gearing - i.e 5 teeth more on a rear 50 tooth sprocket is 10% - and apply that to the revs, so if 70 mph is 4,000 rpm, 70 mph will become 4,400 rpm).
But make sure you go on what is fitted to your bike, not what standard fitment is!
Hope this helps.