12 hole 250cc or 330cc injectors are an awesome upgrade for your 2000-2006 tundra. Stock injectors only have a 4 hole nozzle. By upgrading to a 12 hole nozzle you will get a much better fuel atomization, a better throttle response, tip end, low end torque and better mid range power. the truck will drive more like a modern vehicle. Choose the 250cc if your running gasoline or the larger 330cc if you intend to mix E85 into your gas. Electrical adapters are required for 330cc injectors on 2000-2004 Toyota Tundras.