new speaker question

my toyota v-drive has 4 speakers. two in the bow and two in the cabin. the sound isn't that great at running speeds and if lots of people are sitting in the seats, they are even harder to hear due to their position. When i was in a vlx i noticed their speakers on the dashboard that fire at the windshield. Should i put some 5.25" on the dash or upgrade the existing speakers? if i should add new ones, how should i wire it with my 4 channel head unit?

Get a new amp to run the new speakers, or all of the speakers. It'll sound much better than the head unit only. Just putting an amp on new speakers in the stock locations will help immensely.

Also, add an amplified sub to help bottom end and cross over the other speakers @ 200-400Hz perhaps to help them go louder more efficiently so they don't strain to put out frequencies they can't handle. Definitely get an amp for the mains though.
-tim

ok thanks. if i were to just do one of those things which would you reccommend. btw, i'm getting a sub regardless.

Depends on how much work you want to do. Here's the order I'd tackle things, aside from the sub:
-Initially, putting an amp on the existing speakers would be a good experiment. Get plenty of amp for future use on better speakers.
-Then if that doesn't work, upgrade the existing speakers to better quality.
-If still not satisfied, consider alternate locations in the main area for a couple more speakers or tower speakers, which are easy to hear in the boat.
This way you know what affects each upgrade has on boat sound and will be better educated for the future audio upgrades that are certain to come once you start a project like this.