N802's - Bi-amp or better amp?

Currently running a Sunfire Signature Series II and there's really no pronounced shortfall, just know there's probably better amp situation out there for me. Wondering if there is bigger bang for my buck. Specifically, does anyone have thoughts on passively bi-amping with a couple of 250w amps of good quality, or would I gain more going to a 3 or 400 watt higher end amp like Pass or others? No defined budget at this point, but would buy used. I'm really just curious and thinking about a next step. Thanks!