The Aluminum 100's suck for one reason they fill at 3300 psi. So on a boat you get 3000 that cools to 2850psa you have a huge 80 anyway. I have both, but really like my LP95 and my LP120 both steel for the longer times I might need to get the "Shot". Aluminum 80's are great for cold water, you don't have to stay down as long. I have posted this before, but LP is the way to go because you can get a good fill anywhere.
Bama, 4000 isn't an over fill at all! 4100 maybe! Right?