While I can't say whether or not a single comp set will "keep up" to your level, I've always kind of thought the way SPL guys go about it is a bit idiotic. HLCD + large midbass would be the way to go, IMO. Much more simplistic setup, and one that actually possesses the acoustic capabilities of maintaining good, accurate sound at the same time. Imagine the possibilities of an SPL vehicle that actually imaged well and sounded good from 80hz and up! (when you weren't playing the system at 150db, as nothing will sound "good" at that output level) For one, HLCD are capable of getting loud enough to literally deafen you. Literally, deafen you. If you think 150db of subbass is loud, consider what ~130db of midrange would sound like (if you don't know the difference in your hearing's sensitivity between subbass and midrange, look up the Equal Loudness Curve). And you'd only need ~50wpc to do it. So from about 800hz and up (for a non-minibodied horn), you won't have to worry about being "drowned out" as the HLCD should cause you physical pain long before you had any problems from the subwoofers. Now let's look at the midwoofer. You currently have a trio of 6.5" drivers. The average 6.5" driver is going to have an Sd of around 135cm^2 from what I've seen. If we replaced the trio of 6.5's with a single 10" midbass (Sd ~345cm^2 for the 10" drivers without large subwoofer-type surrounds), you'd only lose about 15% in cone area, which for a given excursion level is a difference of only 1.4db......or just barely in the realm of noticeable audibility. There are some other things to consider, like the possibility of the 10" midbass having a larger Xmax increasing output potential in the midbass region and the possibility of lower power compression, etc. But if we just keep everything equal for the sake of discussion, the realistic difference between a single 10" midbass and a trio of 6.5" drivers is going to be almost negligible. Chances are pretty good that at the output levels you're describing, you won't notice a difference. So there you have it. A pretty simple 4 speaker system that would be more than adequate for your output needs and actually be able to retain some semblance of good sound at lower SPL levels with the right driver selection. No, I've not built a 150db setup because SPL just doesn't interest me all that much. And no, I don't any pictures or videos to show you because for whatever reason most SPL guys don't pursue this route (my guess would be first, it's not as impressive to open a door and see 2 speakers instead of 16 [since horns aren't very visible] and two, it's a simple case of "monkey see monkey do"). But that doesn't negate anything I've said in my post. Pictures might comfort you more than numbers, but the numbers aren't wrong just because they aren't accompanied by pretty pictures. If you have a way of disputing the numbers, I'd be much more interested in that than seeing pictures. Oh.....I do kinda have one example. RC's GN had old school horns under the dash, 12" mids in the rear quarters and a pair of 15" subs at the rear seats....it is said to have been able to do over 135db full range, which is completely different than 135db in the subbass region. A true, consistent 130db in the midrange would get very painful very quickly, and much exposure would leave you with permanent hearing damage.