I use to be sponsored by Critical mass in 2007, when crx's were the thing in street B spl. I found that, for a SQ sub UL12 could get pretty loud. I was waiting for the UL10, but they never produced it. They said there was no market for it. I have hered every SQ sub out there, and I believe the UL12 tops them all. Now for it to be a true 2.5kw RMS sub....not close. But it sure can hang with the big boys. Especially being created as a SQ sub. If I was still into Car audio and I wanted a pure SQ system....UL12 would be my choice.