Old post, but I just got my 20s in the mail yesterday, and yeah she's quite loud when speakers are positioned right. Really glad you've a sena, will make life easy when I get to WA. I fought the same issues with a properly fitted helmet ripping my earphones out sometimes, or pressing one, angling it, and not getting sound from one side.
The 20s is nowhere near as complicated as the reviews make it seem, easy to use, loud as hell, and fits the RS1R nexx helmet like it was made just for it.