ohhhhh okay; I've never heard of that. I know that one dude sells the kit (for the MK VIII) with two, but in all my research, no one in the exhaust industry really believes it will add power by having two types of "x-pipes" over one.
If drone is a problem, would a dual in, dual out with pass through resonators and turbo style mufflers give the tone someone would be looking for? At least that's the route I'd take with it if I were looking for a somewhat mellow/subdued tone with no drone