both systems are much louder in a good way. my $.02 is that the full system is a little louder and i have been on bikes with both. i found the bike really comes alive with either but the upper end of the full system is really a screamer!! the auto blipper is better now, the map is less boggy, etc, etc. What really sold me was the install cost was almost the same at the dealer. i pushed hard on the dealer to get a better install cost for slip on as i am not that fast on the track truth be known.. but they wouldn't budge. they actually came down on the akra full system cost to try to close the gap.