12" sub recommendations (box, amp, etc)

[Connor]

A little background: I currently have a Sony Xplod 12" sub that the previous owner of my boat had installed. It is running on a Sony Xplod 1200w amp. the sub is installed on the drivers side kick panel area in a custom made box. The box is sealed and is give or take 2.5 cu ft inside volume.

My main questions are:

Can I just upgrade my sub and keep it on the same amp and box? If so, what is a good recommendation for that cu ft volume sealed? (JL, Sundown, Kicker, etc)

I would prefer to keep the box just because it does fit perfectly in the kick panel area, is this to much volume for a sealed enclosure? Should I port it somehow, and if so what is the best way to go about that without destroying the box?

I do realize this is broad, and a lot of questions and scenarios but looking for some info on what some of y'all would do if in my shoes. Let me know if any more info is needed. Thanks in advance!

[David Analog]

A little background: I currently have a Sony Xplod 12" sub that the previous owner of my boat had installed. It is running on a Sony Xplod 1200w amp. the sub is installed on the drivers side kick panel area in a custom made box. The box is sealed and is give or take 2.5 cu ft inside volume.

My main questions are:

Can I just upgrade my sub and keep it on the same amp and box? If so, what is a good recommendation for that cu ft volume sealed? (JL, Sundown, Kicker, etc)

I would prefer to keep the box just because it does fit perfectly in the kick panel area, is this to much volume for a sealed enclosure? Should I port it somehow, and if so what is the best way to go about that without destroying the box?

I do realize this is broad, and a lot of questions and scenarios but looking for some info on what some of y'all would do if in my shoes. Let me know if any more info is needed. Thanks in advance!

Conner,
You probably do not want to try a retro port into an existing sealed enclosure. It's a little too complicated for that.
I also am conflicted about using an existing custom box without really investigating it's construction. Any imperfection causing the enclosure to leak can spell an early demise for your sub, not to mention bad performance along the way. Cheap terminal cup, caulked wire with no terminal cup, untreated MDF, no elevation off the sole, etc.
I wouldn't necessarily try to match the Sony amplifier rms rating with a woofer because I seriously doubt the amplifier delivers that much power real world. Sony, while certainly capable of anything technical wise, probably isn't putting their best foot forward in the Xplod series, if you know what I mean.
Most 12-inch air suspension subs will work well in a sealed 1.25 cu.ft. internal enclosure which would be about 1.85 cu.ft. external. Some 12-inch subs are designed for a little less. A bass-reflex 12-inch enclosure might require about 2.85 cu.ft. external.
I would resolve the enclosure issue and have a very accurate assessment of the maximum available external displacement BEFORE selecting a particular sub driver.
When it comes time to select a sub driver, it's helpful to know what your bass performance priorities are. Type of music. Musicality/deep extension/linearity. Maximum peak output. Maximum capacity for abuse. There is no magic pill where one driver does all things. Some people like tight bass. Some like fat bass because it gives the impression of more output. There is no wrong answer. Just personal preference.