Were you comparing sealed or ported? Solobarics get insanse with proper ported box. I built my ported box on a whim, thinking "well if this doesn't work I'll just do a nice large sealed". I had the gains on my amps identical to where they were in the sealed boxes, and the first time I turned it up I freaked out because it was so loud. I double checked the non-fading settings on my deck, double checked my noise gate, matrix and amps, then cranked it up to the setting I usually listened to it when I had the sealed boxes, and no distortion at all, just stomach churning bass. I can't handle turning it up as loud as it will go. It makes me beyond nautious. I thought mine were nuts till I helped a friend install a solo X 18 in a 10ft^3 box in the back of an excursion with 3000w of mmats nut behind it, it was unreal but he wasn't happy. I just got a call from him at work today telling me he has a pair of MA Audio 4400w HC amps. So this saturday I'm installing them and he'll have 8800w going to a single 18, I can't wait to hear...errr. feel it lol.
The downside to my setup right now is it's not very versitile. It likes to play anywhere from 35-55 hz, anymore more or less it falls on it's face, and I mean bad, you can barely hear a 65hz bass note over the mids and tweets on a good song. I'm getting ready to rip this whole thing out and put in a pair of ID Max V2s in BIG sealed boxes (or a pair of PG Elite if I can get a deal on them), I'm past my phase of obnoxiously loud, I want loud but clean, plus I'm sick of buying mirrors, the guy at teh service desk recognized me the last two time I went to the dealer lol. The other downside is size. I can't even fit 2 plastic bags of groceries in the back right now. I might put my little boxes back in for a while, I'm prettymuch sick of the monster box.
I went from this modest 1.5ft^3 each sealed(I know they are facing eachother, everyone has a theory of cancellation, but that would only apply if they were out of phase, since they are in phase it causes the trunk to act like a bandpass enclosure, and they were pretty loud, and very clean)
to this 3.27ft^3 each MONSTER(with port vol about 8ft^3 total)
Here's a box plot I did in winisd, normal sealed versus large sealed, small ported versus mine.(it just look big, it's a gif, so it's small sized)(**edit:ooops fixed this link)
http://home.pacbell.net/peter_s/l7.gif