A canister can give a little performance increase. A tuned pipe gives you somewhat more in the mid range and much more torque at top rpm, up to 30%, and about 10% more thrust at full throttle. You hear people about pipes making the engine peaky and that's because it performs best at a certain rpm the pipe is tuned for. You definitely need to program a throttle curve in your radio. If you don't, one click of throttle increase is the difference between a hover and going straight up like a rocket.

I recommend the MTW header and RE2 pipe because it performs extremely well and is relatively light. My second choice would be the ES Composite pipe.