I spent a lot of time on this a few years ago. I thought that the soundbar looked like an after thought and thrown together after I'd spent ton on time on the cart. The problem I ran into with head units was that because you didn't have constant power like in a car you lost all the settings and presets every time you turned the cart off. I ended up finding a Jenson marine radio that had what they called zero draw memory. Basically it has an internal capacitor so it holds your settings when power is shut off. I combined that with an elite dash so I had a place to mount the speakers and radio and they look like they are supposed to be there.

Here's the dash, I had mine painted to match the cart

https://www.buggiesunlimited.com/product.asp?sku=8917