What exactly is a High Speed Build?
In airsoft a high speed build refers to a upgraded platform (usually PDW or PBR) capable of a fearsome rate of fire (30-50 rounds/sec). High speed builds are typically medium to high stress and require moderate tech skills and basic knowledge of the inner workings of your rifle.
What gives your rifle a high ROF?
The ROF (rate of fire) is determined by three things: The battery, the motor, and the gear ratio. Ultimately the battery affects the ROF the most but motor and gear ratio are equally important. Even with a powerful 11.1v LiPo your guns ROF will be heavily restricted by its stock motor and gears. Upgrading your motor and gears will allow you to use the full power of your battery and greatly increase efficiency and trigger response. To handle the high stresses that these new parts will put on your system you will need to upgrade parts such as the piston and spring. Modifications such as radiusing and short-stroking may not be essential but are highly recommended. Shimming and motor height tuning should be done on ALL builds and is a must for stress builds of any sort.
Understanding what parts to buy
Battery: First things first, throw away every Ni-cad/NiMh battery you own, you wont be needing them anymore. . .