with regards to the pros and cons of leaving the tray off, I suspect something that solid and heavy, and looking at where it bolts to, it is more than likely structural so I would recommend leaving it on.
Takes 15 mins. to remove, so whats the problem?
It may be a pain in the ass but mine served its purpose in the floods around hull last summer - it makes a lovely raft!
why not just cut a hole in it where the sump plug is??