I have got over 200 hrs on my IMCO standoff box with the torision bar shaft and have had zero problems. for the last 30 hrs it's been pushing about 1100 hp.

Is there any vibrations with the stellings? Also what maintenance is required

No vibrations that I've noticed. Maintenance is just pulling off the side covers every 30 hrs or so and greasing a few zerks.

Actually, my engines are moved forward a foot and I have a short driveshaft. No coupler though. It was set up this way originally when built. They could have and it probably would have been better doing it your way with the coupler.

I would have just used the solid flange and the short slide shaft supplied with the boxes but since I had the driveline stuff sitting on the shelf and the couplers left from the Bravo drives I figured that it might be a smoother easier load on the drives. I had heard that shifting into gear was a little hard if the rpm's where up a bit. As for any vibrations from the Stellings? The only thing that would cause a vibration with using a box would be either a misalignment of the shafts or a joint going bad which could happen with any box or installation. I have delt with Stellings service and I am very happy with their service, advice and knowledge of their equuipment. I decided to replace all the seals and bearings in the carriers before I install the boxes since I bought them used. I also went with their beauty inner rings which have no rear mounts or inner steering provisions, rather than use the bravo inner plates and cut them to clear the shafts.