Thanks, that answers it... it's worth useing the airborne and I will ditch the sidewinder piece.
If it is the 5th airborne/sidewinder I don't think that you can ditch the sidewinder piece.
I have the same pinbox and have used it on 1 long trip on I95 and did not notice the chucking and banging from all the potholes. IF you got him down a few hundred dollars the "airborne" part might be worth it.
The "sidewinder" part can also be made into a standard pinbox with a couple of bolts.
For reference, I think the sidewinder\airborne is in the $1600 range new.