I want to seal off my trunk because it leaks on occasion, which i think I have fixed, and because I hear it will improve my bass response as well as reduce road noise. I'm not looking for sound deadening advice because I'm going to do that this summer and I know what to do about that.
My question is, what can I use to seal off my trunk (no air in or out unless I open it up)? I realize I won't be able to seal it completely unless I weld the trunk shut but I want to get it as well sealed as possible while still being able to open it. I've heard of using Great Stuff but I was thinking of using a rubber sealant spray like Flex Seal instead but I'm thinking thats gonna be pretty expensive so whichever you guys think is better.
I do not want to seal my car off from the rest of the cabin, just the outside.