more info needed. theoretically if both setups had the same power, the 12 has more cone area so they should be louder. but too many other factors to consider
possibly an alphasonik hca1000 which does 3000 at 1 ohm, does about 2400, its going in a 1994 buick regal. gonna run the stock power setup, maybe throw in a deep cycle battery, the 2 12's would probably be on a usa 2000 oldschool amp that does 1000 at 1 ohm x 2. 2000 at 2 ohms bridged, MT and hdc3 on the alphasonik amp