Does anyone know of a place that sells boxes made for 4 L7 Kickers that will fit in a 2004 MCSS? Or how much a custom box would cost to have built? Pics...anything would help. thanks!!!

 

You'd probably have to get one made to fit, doubt they have any prefab boxes that would fit in our trunks to hold 4 L7's. what size subs? Maybe a custom fiberglass enclosure?
I've had a single 15" in a 4 cubic ft ported box, it took up most of my trunk space

This one holds 3 and I doubt it fits lol

3 Three Hole Square 15" L3 L7 Grey Subwoofer Sub Speaker Enclosure Box | eBay

 

Are they 10,12,15s? You could do 4 12s sealed or 2 15s ported but it would be a huge box.. My 4 15 ported box is a 23 cube wall and most of my car has been cut to make it fit