Hello,
Advantage are abvoiously much more power and quicker throttle response. Disadvantages are the cost and the size.
If you wanna try a tuned pipe then get the "flatdisk" type as they are tuning much broader and easier for sport applications.

These people have the flatdisk , they call it purple pipe, and header you need.

http://www.justengines.unseen.org/pipesjen.htm