I have a pair of Mille Pro's in my fairing and like them. They have a well-rounded sound - good mid-range and bass; not too bright. Loudness is okay to me. I think it depends on what amp you power them from and what your setup is. Mine are powered by a RF T400x2ad and they are my primary speakers.

 

Amp is still undecided, although 95% certain it will be the Moto 600.4 due to adjustability. I would also consider bridging this amp to the MLK 165.3 if you thought they need the extra power. Then figure how to stuff an additional NVX MVPA4 bridged to power the existing Polk MM651's in the tour pak pods. Oh, I guess I should have mentioned this is a Rushmore Street Glide. My goal is to maximize a 4 speaker set up with all amps in the fairing.

 

FYI --- you can't bridge one if those amps to a set of polks. Most class d amps are 4ohm stable when bridged. Those speakers are 2.7.

 

So for this scenario I'd have to swap the rear tour pak pod speakers with a 4 ohm set.
That being said would you recommend staying all hertz and using HCX 165 or MPX 165.5
or go with the moto 602 considering any of these options will require spacers?

 

Either of those would be a good choice but you could also go with EVF 165s as a replacement. Shallow mount 6.5 in speaker that doesn't require a spacer.