Replacing stock speakers in Nautique Super Sport?

I need to replace the stock speakers in my '97 Super Sport. First of all, I was wondering how do I remove the stock speakers behind the panels. I think the panels come off. . .but how? Does anyone know what size the speakers are. I think they are 5 1/4". If that's the case, I have been considering replacing the stock speakers with some Infinity Kappa 52.5i's or MB Quart Discus DKD 113's. Does anyone have any opinions on these speakers or any others that aren't really expensive? Thanks.