[Darren]

I think you'd gain quite a bit by upgrading your amp. I'm not sure of the new Tempest specs though. I have 1,500 watts going to 4 RLP-15's and I cannot bottom them out no matter how hard I try. The amp gives up first. When I had a single vented Tempest I ran 250 watts to it and it performed well. I'd suggest going to 1000 watts or more and just keep the gain in check, that way if you decide to add 2 more drivers in the future you are covered. Going with a bigger amp will gain you significant headroom and you drivers will perform well. I'm willing to bet you haven't heard nearly what those drivers can do in an IB with only 150 watts.