I bought a Pitbull trailer restraint a couple of years ago for my '07 GSA. I love it and it performs flawlessly. For those of you not familiar with the Pitbull system, it does not require any straps or tie downs at all. It does not compress the suspension and allows the bike to "float" on the trailer.
My concern is regarding the swingarm pivot bearing. The swingarm assembly was not designed for the torsional loads that this puts on it. I have not had any problems and I just returned from a family Thanksgiving reunion that got me out of the sandbox for a few days.
Any thoughts or suggestions would be appreciated, here are a few pics of my rig: