I can’t comment on the Polks but IMO the closest sounding speaker you might find to the M80s locally to listen to are the Paradigm Studio 100s.
Unless the return shipping is going to be prohibitive $90 USD for a pair of M80s I suggest you order them and have a listen. No better way to test speaker than in your own room with your own equipment for 30 days. Make sure when you test them you use well mastered CDs. Good speakers make bad recordings sound bad and great recordings sound great which is why many people don’t like “detailed” speakers . . . because they have a bunch of crappy CDs.
IMO you don’t need SACDs either. I like them for multi-channel but well mastered standard CDs can sound just as good. Best place I found to get well mastered CDs is a local high end audio shop where one of the owners and I have similar tastes in speakers. It’s been worth buying from him both because I can demo them before buying and because he has great taste in music.
