I ran my fully loaded Bl on 1500w daily, took it like a champ. I don't have any number though.
Your profile says you're from Sandusky - if you wanna trip it down to Sharon PA you can play around with my 12" Bl if you want. Its in 2.3 cubes @ 32hz, got decently loud & still sounded good doing it.
I gave 4 18s about 2k, not daily cause I have everything on a switch but i played them sometimes 3-5 min and they didn't get hot. But i have heard 1500 is there best.
i got my 18's on 1500 a piece right now but i want more so im gonna double the power and run an ap30001d on each sub, im kinda scared what might happen, i used a ph5000 at 1ohm on the old bl 18 and it handled it decently