I listened to both two days ago, and ther eis a sound quality difference between the two, I was torn on the dicision as well. I decided to go with it almost for the sole reason of the dsp, being able to fine tune the freq is a plus. also you get the cd player 6 disc(which we probably wont use).
both models have the subs, but sound quality wise I would say it is worth it, if you car about quality, they are both loud if you jsut want to crank it up save your money, I felt that they were pretty equally loud, jsut the quality is better .
hope that helps

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M3