Paul,
Tire pressures are too high, in my opinion. Many of the drivers on the board run five or six pounds less in the front than the rear. I am currently running 23# front and 28# rear which gives me good handling. I also have a swing axle, but no suspension mods. All is as delivered from VS. The rattle you are experiencing, could it be the doors? This has been a continuing problem with my car, but mitigated by adding or replacing weather stripping to give a tighter seal. This may not be what you are experiencing, but when you said you were hearing the noise even over small bumps, it brought the problem to mind; This was the symptom I had.
Good luck
John H
2000 VS