I got a new amp, and I think it's about to put a hurtin on my Rl-P12 D4.....It's a Clarion DPX11551 so at 2-ohm, it will be putting 1550RMS to the sub.  It will be sealed in 1.25^ft.  If the gain is all the way down, will I be OK?  Previously ran with 500wrms, and it was a monster. Also, whats the highest I should cross the sub?  Im running Dayton RS180-4 7" in the doors.  Can I cross the sub at 100hz or am I asking for trouble?  Thanks.