I took my two sealed 10" kicker cvrs, powered by a kenwood kac-1904d, and was looking to get ported 12s of the same brand. Should I expect a huge difference with the same amp?
First of all, you should never use the word audiophile in the same sentence as Kicker. That's just down right disgraceful to audiophiles.
Depending on the design and build of the enclosure you should notice a difference. How huge it will be ... depends on the design and build of the enclosure.
it depends on what ohms your going to run them at,and if your charging system can handle a bigger load on it without an alternator upgrade.go to 12volt.com and look into the BIG 3 UPGRADE,if you don't do the upgrade you should not waste the money because a system is only as power full as your charging system is power full.and a second smaller battery is also needed next to the amplifier to store energy for when the sub woofers call for it.the lower the ohms you wire the system the bigger the draw on your charging system, 2 inches is not that much and you will need a new en closer for the 12s it has to be bigger in cubic feet.hope this helps.you can keep the tens and upgrade the charging system first and them 10s will hammer.then you will head the difference.you won't need the 12s take up to much room.