SnakeFace wrote:..... I'd like to know your thoughts on both advantages and disadvantages of these systems......
before you spend money on PC's - get a dyno-tune now, so you know what your baseline fuel curve and hp are. Ideally, you would do this somewhere you can get a PC3 or 5 tuned up anyway, as any follow-up dyno tests need to be done on the same dyno for consistency.
As Blurr has said, they just fill in the dips and bumps in a stock power curve - this results in a much smoother power curve ( as Lurch has found out) - you may get a few extra hp, if the stock exhaust is really restrictive, then getting a good 4-2-1 (ditch the twin pipes) and a better air filter - you may pick up 10-15hp or perhaps even a bit more on some bikes.
A few years ago, AMCN fitted an Akropovic full system and Dynojet kit to a long-term project bike they had - it was an 1100 or 1200 Bandit. The hp on this bike rose by almost 30-odd hp with these mods !!

It was a shock to these guys as well, they never expected such an increase.