Like he said dropping a tooth on the front is like adding 3 teeth to back,the smaller the front sprocket is the faster you acclerate.I wouldent go any lower than 14 because the smaller the sprocket the faster it wears out.
Heres what i'd do
Pipes
Coolhead (domes depending on what gas you want to run)
Vforce 3 reed cage and some reeds
Trinity 35mm 2in1 carb
Port the sh!t out of it
I would stick with bottem - mid end so you get the holeshot