So the takeaway message regarding speaker sensitivity and pre-out voltage: let them be more like ideals to shoot for but not to become too absorbed in.
In the real world on a motorcycle they may make only a tiny bit of difference in how loud and clear your system plays.
Go for a head unit you like the looks and functionality of. Go for one with built in crossovers.
If you are going to amp it, try to get a head unit that you can shut off the resident amp on (can others chime in on this idea please? Does it dininish power draw enough to warrant seeking out this feature in a head unit??) and use shielded RCAs.
If you see two head units you like, and you are going to run an external amp- get the one with the higher pre-out voltage. Otherwise don't even think twice about it- sound quality difference will be minimal at best.
Go for speakers that are "free air" or "infinite baffle" or rated for largest size cabinet space if your fairing isn't well sealed. Go for the highest sensitivity you can find in that design.
If it is well sealed- you'll find higher sensitivity (Db) options. The higher the better for greater efficiency.
Go after speakers that rate well in terms of sound in a similar application (free-air/IB, or sealed/small compartment/cabinet) with similar power.
If that level of research is ridiculous for your time/interest level- try to find a set that people like and then look at the power handling ratings for them. Particularly RMS. If its rated 125 watts RMS you definitely won't have enough power to make them sing with a resident head unit. They might sound good, but not as good as people who powered them correctly are saying.
Also- higher RMS means more juice needed in general. So get ones rated more conservatively.
If you like your highs bright: titanium or aluminum or metal-du-jour tweeters.
If you like them smoother and more laid back: silk dome or whatever fabric-du-jour. Not sure how many options exist in a weather resistant speaker.
In general- pricier head units will sound better. If you are comparing in store, and plan on using the resident amp on the head unit- the weight of the head unit can be a clue.
Now stereo manufacturers love to claim their amps (wether resident or external) are able to put out XXX watts. But they are usually talking peak watts. So you gotta look for the "continuous" rating. Not "peak". Peak means nothing but marketing lies based on something you'd never want to listen to (or could even hear- but that's another story).
And even with continuous, some manufacturers are conservative, some are nearly spot on, and others lie. Most are close in the better brands/non bottom end models.
So stick with known and better brands and the more expensive units. You will likely get what you pay for.
For speaker wire- buy whatever is on sale. Lamp cord is fine if you want overkill in terms of gage.
For power- get a beefy wire- and use the same gage for ground.
Others can suggest where to tap, where to put the fuse and if you should use a relay for greatest clean power.
Let us know how it goes!
Sent from my iPhone using Motorcycle.com App