to the forum! All I have to ask about your idea there is, are you sure you have enough width to get four 15's in the trunk of that car with the correct air space for each and not have them stifled? If so, then I think your build idea with them on each side will look really good. I know those cars have ridiculously large trunks, but four 15's should need at least 14cuft of enclosure space. I looked at DB Drive's website and they list 2.66cuft for those 15's which seems absolutely absurd to me. I know of quite a few 12's that need space in that range to operate properly, it's hard to imagine 15's could and still sound right. I'd run some numbers and see what the T/S specs say would work best and see if that will fit in the car. I think the manufacturer has listed a super small enclosure size to make it more appealing to people since the vast majority of people hate giving up any more space than they have to. You may be much better off looking into 12's if you're wanting to do four subs.