The gold series is an awesome all around pipe. If you want to convert the power more towards the bottom end though, you will need to do this.
This is what is done to my bike, and it makes a ton of torque and mid power.
Dynoport 2 into 1 pipe with ultra quiet silencer.
Dynoport Port job.(yes dynoport does port work for the 2 into 1 pipe).
2 into 1 trinity intake with 35mm pwk and K&N pod filter (you may want to run an airbox though)
Stock reed cages with carbon tech low-mid reeds.
Flywheel lightened. (rs heavier magnet flywheel).
Cascade Heavy duty clutch kit.
+4 timing advanced.
Pro design head with 20cc domes on 92 octane pump gas (155 psi comp).
13/46 gearing.
Wiseco Pro lite pistons.
Its a real strong running bike, amazes a lot of people, and its easy to keep on the pipe at slow speeds.