qldit

Good Morning Wayne, from my experience I try not to use really heavy wattage speakers because they usually have a "hard sound" and need a lot more power to drive.
Always try to use speakers that are adequately power matched to the amplifier.

The way the speakers are mounted has a lot of effect with sound quality, but cheap radios usually are not capable of really good effect.

I would suggest temporarily trying a couple of reasonable speaker enclosures with similar speaker impedence and wattage just to see if the radio is capable of decent sound. These might be simple ones from a home stereo player etc.

If you do try this be careful with the speaker leads and ensure the thing is not powered before you experiment.

Chances are you will find your radio is lacking.

I like Clarion and Pioneer brand radios but you will have other decent brands available there.
Many cheaper radios also have poor distance pick-up so watch out for the "you get what you pay for" part.

I am assuming you have front and rear speakers.

If you spend a fair bit of time in your machine it is worth getting a reasonable radio, in the area of at least 20 watts per channel with internal amplifier in the actual radio, this keeps it simple.

Others will have different ideas.

Cheers, qldit.