I highly recommend the Basslink. I've had one since they came out and they're awesome. No, it's not as loud as 2 12's but it still puts out a lot of good, clear bass.
Stay the hell away from Bazooka crap unless you like semi-loud fuzzy, muddy, annoying bass. I had a place recommend Bazooka when I was first looking at the Basslink so I went ahead and had one installed. I think I drove about a mile and a half before I turned around and had them pull that piece of sh*t out and put my Basslink on order.