My Wellcraft 180 Fisherman CC was like swiss cheese when I got it. I installed Pyle self-powered blue tooth speakers to fill the holes that were already there. Not the loudest while underway but they did the job. It's all about speaker placement.
I just don't have the heart to cut holes in my unmolested 1801. It was a buying point when I purchased it that nobody added/modded anything to the boat except the battery charger.
I use. a
W-King D8.
There is a newer version also
Newer W-King D8.
Mounting speakers in the bottom of the console pointing out to your feet to me is counter productive for good sound.
If you have a t-top that's a different story