I've had my 06SG since it was new and have had no problems. The only thing I wasn't happy with was the weak and noisy front brakes. After replacing the stock rotors with floating rotors and adding braided lines, they have been fine. It's a great bike and I'm completely happy with it.
the only issue I've had with my '06 is the inner primary main shaft seal went bad, look at the front belt sprocket area for an oil leak or dampness, if there is, make them fix it.
I bought mine used in 2006 and didn't have any problems. There are TSB's for the motor mount, steering lock and moving the mirrors to obtain a better view. HD corrected these with no issues. If you want the TSB info, PM me an email address and I'll send them to you.