Greetings,

The macs pipe is a tuned muffler that will add some rpms and still give good torque. It is a one piece unit and very reasonably priced and easy to use. Tuned pipes are usually tuned only for top rpms and power, very peaky, and may hurt the low end torque. These are best for high speed or racing only.

The nod definitely goes to the macs one piece pipe or muffler for sport flying.

Ernie