In my experience, a ported box will be only a little bit more louder than a sealed box but will deff. put out a lot more deep bass which most people want. I have two Kicker 12" CVRs in a sealed box with 1.5 ft^3 per chamber and it hits really hard and takes your breath away. Don't get me wrong, I have really good deep bass but my friend who has the exact subs in a ported box with the same power going to them will play lots lower than mine but on a db meter the difference is only like 3-5 db. Crucial for comps but not really noticable for daily driving. Ported boxes need to be built perfect too and are bigger than sealed. If you want to get as loud as possible for those subs, get ported if you can. That will squeeze every db out of them and will make you say "Damn, I can't breathe!" Should anyways with correct power going to them. I should add that I only have a sealed box because one of my friends gave it to me and why not use something that's free?