I want to add a dual sealed 10 inch sub box in the boat. Do I need to have it custom made out of marine plywood, or is a pre made one that is made out MDF ok. It will reside under the observers seat in an 07 X2.
You can buy a prefabed one but I would recommend a custom one based on the exact specs of the subs you are using. Either way, having it Line-X'ed or such will ensure it lasts forever in the wet environment.
Matt make your enclosure out of mdf like normal then go to home depot and get epoxy resin for fiberglass mix it up and brush it on. Put a few coats on then sand smooth for paint or put carpet over that. I did this three seasons ago and it is still showing no signs of wear Dave