Stereo Install Help

So I have a 2003 bayliner 185. I know not a wakeboard boat so dont trash me. I am going to put a stereo in it. Question--how do I support the radio once I do the GelCoat/Fiberglass cuts and push it through. Should I make a wood brace and glue it to the backside of the fiberglass? Also cutting a hole is scareing me a little. I hear a 5" hole saw should do the trick for the speakers. But how do I cut the rectangle for the head unit?

Thanks

Where are you going to put the HU? A pic might be useful.

Some Head Units come with some additional bracketing that will help give some support.

Here is a pic. Doesnt come with any brackets just that small sleeve

The fiberglass itself should support the weight of the radio. With the hole saw I'd recomend drilling in reverse, worked great for me....I din't even haev to tape it. Cutting out the rectangle I would tape it off.

You cut the holes with a roto-zip. You should be using a marine radio install kit. That will support the radio

any specific blade on the zip?

Also Where can I find a Marine Radio install kit? I googled but could only find the covers

Thanks