ROKS - the part where the pipes join up is the resonator. There was a post elsewhere on here the in the last few days where someone mentioned that a dealer said the exhaust was routed through a single resonator at some point.
I wonder why there's such an extreme difference in the routing? And that they put the mufflers all the way in the back? Hm...
The single resonator probably provides a crossover point between the exhaust which generaly makes it sound better and helps ballance the exhaust between the tips. Most aftermarket exhaust use a crossover pipe at one point or another.
Looking at the picture, it has two inlets and two equil outlets for the resonator. I have no reason to believe that this is any more restrictive than two seperate resonators with a crossover pipe elsewhere in the line.
Personaly, i'd be more interested in knowing the pipe diameters and if it has crush bends that pinch it off at any point. Also if the mufflers are straight through or not.