I'm kinda in the same boat. I've got an Alpine MRD-M1005... trying to decide whether to go with 3 Type R 10s (have a sealed box for 3 10s is my only reason why) or 1 Type X 12. I have had both 10s and 12s and want something that can keep up with some quick bass but also have pretty low extension. I've had both Type R 10s and 12s but never the Xs. I'd get two but then I'd have to get another amp as they don't make dual 2 ohm Type X Subs. I know that technically, because of the greater surface area, the 3 Type R 10s would probably be 'louder' than 1 Type X 12, but i was curious what othe people's experience with this are. I'll have a fairly decent front stage- SPX-177R run active off a MRV-F545 and a CDA-9887 headunit. I want bass that will keep up but also be clean and not overbearing. Suggestions?