This is the popular -1+2 gearing mod.
15 Tooth Front Sprocket
44 Tooth Steel Rear Sprocket
BLACK Vortex(Mfg by EK) 112 Link 520 SX3 Xring Chain.
NO CUTTING NEEDED
520 sprockets are one of the best performance mods you can make you your bike.
The smaller chain offers less weight and drag which transfers into MORE POWER!!!!