Originally Posted by m4a1mustang

Drone is a touchy subject. Everyone wants to defend their exhaust, and "drone" can sometimes be subjective.

The FI CBE will give you up to 20whp, but in my experience it drones quite a lot under load.

The Stillen CBE is also good for nearly the same gains. It's quieter than FI. Not really sure on any drone.

Berk should be in the same range power wise and from what I have experienced there is NO drone with just the Berk CBE. I installed b1adesofcha0s' system and rode along / drove it a bit and liked what I heard.

Not really sure on the others. I have seen dyno charts on the NISMO CBE showing around 8-12whp, and I know for a fact there is absolutely zero drone with those systems. The only downside is they aren't quite as loud as the other options.

For a DD I lean towards Berk or NISMO depending on the sound you want.