I helped (and continue to) develop the SA8. I wouldn't do a 3" port. You can run one sealed and it'll be just fine, but that doesn't mean you're getting your monies worth. Ever put 4000 watts clamped on an SA8? We've tested all power levels i ran 2 3ks strapped @ .5 each on 4 of em i dont think he cares about 4k on one driver. He doesn't care about your 2 3k's either. Power levels don't matter when your box is wrong to start with.