I have friend who have RM01A and Power Getter.
The RM01A is louder abit tha power getter when idle but quieter when in vtec.
According to Dyno, power getter gives slightly more hp. (maybe it was just the tempreture that day oso).
For sound, fujitsubo is more low note. Sounds like a bigger engine.
I'm using a Trust PE2, damn kau noisy in vtec. But the sound is nice a crisp. noisier than fujitsubo.
why not get mugen twin loop :D the sounds is beutiful!! *drool* soooo nice!!