Well, if you listen at 103 dB regularly I can see maybe needing more power. I can also assume that you're deaf, lol. What kind of volumes do you listen at? If you ran any kind of calibration you should be getting 85 dB at 15' when your volume on the relative scale is at "0". That's cranked up pretty loud and you're using 3 watts at that point. The other 297 watts are unused and have no effect on sound quality until you get into jet engine volumes...
If you think something is lacking then you need to look into better speakers. Maybe add a sub if you don't have one. Bigger amp will only help if your goal is to weaponize your system. I do not think your gonna hear any audible differences from one to the other.