speaker recommendations

By "hooked up the ones I bought to another radio by themselves and they sound awful" do you mean you hooked them up and they were just sitting on a work bench or on the floor or something? Speakers need to be mounted to a panel, preferably some sort of enclosure, be it a box, trunk, door panel, or something. Different size enclosures will vary the bass response, but just setting open will sound awful on any speaker. The positive pressure wave of one side of the speaker is canceled by the negative wave of the opposite side, unless you isolate them.