Movies are very, very sub dependent if anything blows up in the movie. I have Aperion Audio 633's with two 6.5" mid-bass/woofers and although they have great freq response, a 6.5" driver cannot move enough air to feel explosions, bass in pop music, deep classical music, etc. The M80's have two 6.5" woofers, barely enough cone to equal one 10" woofer. Not gonna get it in my book as far a bass is concerned.
I've been chasing bass since 1981 when I got into audio gear. Over the years, Subwoofer technology has grown by leaps and bounds, and now you don't see many floor standers with 12" woofers in them, and I believe subs are the reason.
I would buy either M50's or 60's (probably the 50's) and go sub shopping. The price difference between the M80's and M50's leave a nice $500.00 plus budget for a sub. The mids and highs from M50's along with a
decent sub will rock your world. You'll be much happier in the long run I believe.
Just for reference I've owned a Hsu Research VTF-3 HO Turbo (top of the line), and sold it to buy my new baby, an SVS PB 13-Ultra. That will be the 5th. subwoofer I've ever owned. I'm a bass junkie, watch out, its addictive

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