For absolute bass slam, I would go with M&K 150/350 or go "all the way" and get a 5000! I also like the SVS models and when I construct my new theater, a larger room, I plan to add a passive SVS model, much like RAF has done, using my spare Carver TFM35X to power them giving me a 700+ watts of power. I would then use it as a Sub-subwoofer and operate the M&K 80hz down and theSVS at 40hz down. That should give me some awesome bass. Whatever you chose, SVS, M&K, you are going to be pleased. I also like the Tannoy subs/ very musical and tight like the M&K!