Repower question. F250s to F300s

If I take the F250s off of my 31 Contender and replace them with the new F300s, how much difference will the less weight and more power make? The weight seems negligible. I would imagine that having the livewells and fresh water tank full would amount to a bigger difference (100ish pounds total), but don’t know what to expect in terms of cruising speed and efficiency with the extra 100 horses.