Paul,
I don't have any practical experience with the D&D's and Beetle bag combination,
that said, see if this makes sense to you.
The D & D's look a lot like the stock and TOR exhaust,
EXCEPT they're more open for a louder tone and they go straight out
instead of angled up and out.
Since they hang lower, there shouldn't be any problem with mounting both
as the design of the D & D's is along the lines of the stock exhaust,
only straight out instead of upswept...
IF that's the combination I wanted, I sure wouldn't hesitate to get it,
it's close enough you can "make" it work.....
just my take on it.
skip