Hi, I have owned two Vandy 2wq subs for almost 10 years, they integrate very well with my Gradfent Revolution mains (passive version). About a year ago i read about the swarm DBA system and decided to add two passive 10 inch B&W sw10 subs with the Dayton 1000w amp that is used for the swarm system. It works okey having the Vandy subs in the front and the passives on the back, but really the Vandy subs make about 90 % of the spl of lows in the system the system, I don,t know if those B&W subs are not adequate ( I think they are more marketed for HT instalations and are not very efficient nor musical), those are 4 ohms and I,m connecting them in series to make the load 8 ohms. Do any of you can recommend to upgrade those back passive subs, preferably with some DIY solution where i could buy just the drivers and make the enclosures locally. i,m located in Mexico and ordering a couple of Audio kinesis subs would be very expensive to ship down here. I have a gut feeling that those B&W subs can be substitued for something better and that this idea of combining both aproaches can work. What do you think?