IB3 is Infinite Baffle, best for sq, not for your goals. Running 1000watts either way is going to need new wire, 4gauge isn't enough unless your only running it ~10ft. To me it seems your rushing, you want something loud but can only spend xxx. You already have a nice amp, take full advantage of it and use drivers that take full advantage of the power. Your gonna need to replace that 4gauge, and probably gonna need another battery for the amp. The only reason I'm suggesting you go bigger and spend more is, you have a big amp, if you didn't intend in using all it's power at some point then your probably would have bought a smaller amp. So instead of doing a small build and then redoing everything in six months, I say wait til you can do it all at once, it'll be cheaper in the end. Just my two cents