The Quest Marine Speaker with Cover - 5-1/2" Diameter - White # 292-100089 will have a cutout that is 3-1/2 inches. It has 4 Mounting holes measuring 3-3/4" center to center to secure the speaker and cover to the cutout. I've attached a video to assist. view full answer...
The Jensen Marine Speakers # MS5006WR has an edge to edge diameter (including the grill) of 6" and the mounting hole center to center distance is 3-3/4".
If you're wanting to reuse the old mounting holes then you would want the Jensen Marine Speakers # MS6007WR instead since they have the same 4-1/2" spacing. They have an overall diameter of 7-1/8" so they'll match up nicely with your current speakers. view full answer...