Hello, I have a 2000 Crown Vic Police Interceptor. It has a heavy duty battery and a HO 130 amp alternator. At the moment I have 2 Kenwood 12's (Yes, I know they're not that great, but they get the job done at a cheap price ) with an alpine 500 watt amp. I was happy with this setup until it quit working a couple weeks ago The amp just cut off, and I haven't been able to get it back on (I checked the amp fuses and the in-line fuse). I think the amp is fried, but I'm taking it to get checked out in a couple days. If it is fried, then I'm going to use this as an opportunity to upgrade. I'm thinking about getting an 18" Fi BL sub and possibly an AQ1200D (unless you think I should get something different. I'm open to anything). I keep hearing about people needing to upgrade the big 3 when they get 18's because of the amp's power usage. Is my alternator sufficient to power this setup? Also, how loud would the one 18" Fi BL be compared to my 2 12's if I build a ~7-8ft^3 ported box to Fi's specs? I've been told that 2 15's might be louder, but I'd like to get the awesome lows that the 18" can produce Thanks, Joe