All the floorstanding Nautilus definitely rock. The salesman who sold us our N803's is buying a pair for himself, and rock is all he listens to. Several things you should consider regarding the N804's...
We have the N803's in a 13 x 18 room that's wide open behind the speakers to another room of the same size. They play loud enough to strip paint off the house next door, with a revelatory clarity and tightness. The N804's would be *inadequate* for this space. YMMV.
150w/ch may be okay, but current delivery is more important than wattage. These things will suck many amps dry. Check your amp's specifications into 4 ohms. If your wattage doesn't double from that 150w/8 ohm number you'll have to upgrade, as others have suggested. You may have to anyway. Depends on how loud you play and the cubic volume of air you need to energize. If you're lookin' to throw open the windows and rock the neighborhood, a new amp is definitely in your future.
All the floorstanding Nautilus models have incredibly musical, fast, tight and revealing bass, but the N804's do not go as deep as their bigger brothers. You may not miss that lowest 1/2 octave, but then again you may. The solution would be to add a high quality sub. Not some $300 POS, more like a Rel Strata III or maybe one of the new B&W subs that match the Nautilus. Not cheap.
Be prepared to fling some of your recordings out that open window. I don't listen to very much pop/rock so I can't tell you which ones, but I guarantee it will happen. There's nothing worse than a bad recording on a good speaker. You won't know or believe how awful something can sound until you hear it. Good recordings, OTOH, will make you dance, make you smile or make you cry.
There is no way to live with these blazingly fast and revealing speakers in a cheap setup. They will suck you into upgrading everything else in your system in an attempt to match their quality. You have been warned.
Whatever you do, enjoy the music!