but what happen if I run it in stereo? It's less dangerous for my speakers?? Isn't it the 500watts rms Power Handlingof the 410hlf enough to support de 450watts in 4ohms of the poweramp??
It will run fine in both modes. Better to bridge it though. More power equals more headroom for your tone - you will not risk clipping the head when powering one speaker to it's max. Don't boost anything below 80hz on that setup - you will run out of power faster than you think. Keep the low end flat and have fun!