sergtech wrote:
I have the XMD3 Sirius system on my 05 Vista.
You don't mention which model Vista. Update your profile and add your location. Then most of us put out make/model/year boat in our signature. It helps the rest of us figure out the right answers for your model boat and location. Like whether your Vista is already wired for the arch speakers or not. I think most models all share the same wiring harness so the speaker wires may already be present. The easiest way to tell is to get inside the space and look for the connectors.
That said, nothing is really going to help make the music listenable when running at speed. The wind and engine noise will just overwhelm your ability to hear anything. That and the louder you make your stereo the more you irritate the other people on the water. Honestly it's really annoying to have to listen to someone else's music as they approach from a mile away and then even louder as they depart. I like all kinds of music, just not when it's from someone else's boat.
If you don't already have an amp, make sure anything that's installed is in a properly ventilated area. Amps tend to get pretty warm when you crank up the volume. They also draw a lot of wattage, so be sure about your battery capacity.
You may also want to consider speakers that are angled more toward your listening position. Either with speakers that have the ability to be aimed, or with some angled trim rings to pivot them a bit. That might help improve things.
But without knowing which model Vista you've got it's hard to be specific.