The speakers mount at the bolts/clamps holding the mirrors on the handlebars. However, some I have seen were mounted using clamps purchased at the hardware store to mount them separately on the handlebars.
At 80mph still loud enough to listen while cruising down freeway to work. As long as it's a 12V battery you're golden. Most power sports batteries are rated around 15Ah (amp hours). Depends on the device being powered the Ah rating means if your device requires 15amps to operate, the battery will power it for approximately an hour (that is if it can discharge at such a high rate without exploding). The Boss MC400 draws a little less than 1/2 an amp (500mA). A fully charged battery will run this system 25 to 30 hours without requiring charging.
Depending on how much space is available on your handle bars, remember your speakers are most likely going on your handlebars. Take note that the speakers are roughly 4" in diameter. Should you have enough space you will need to custom mount the amp on the handlebars( maybe using zip ties). I would not recommend as the amp can get wet and damaged. Once you set it up you don't need to touch the amp for anything as your volume control comes as a wire. Hope this helps. Any other questions feel free to ask.
It will fit anything if your handy enough to drill holes to mount it..maybe some mild fabrication..
I will say at highway speeds the music cannot be heard clearly..sounds great around town 45mph or lower...I ended up putting mine on my ATV