Okay, wait... Is the NSX unitbody construction, or does it actually have a frame? I was under the impression it was unitbody (like everything else in modern times) and not built on a "proper" frame.
For example, with my convertible (98 Camaro), I bought subframe connectors for it (they connect the front "frame" to the rear axle by way of the lower control arms). This helped a lot with flex and I noticed a marked improvement on the first drive.
They bolt up (or weld in) just aft of the front wheels, and the lower control arms are fasented to them via a bolt through the underbody, the subframe connector, and the control arm.
Does the NSX already have something like this?
Also, for those with a frame of reference, how comparable is the T-top with top ON to a coupe? I would have imagined that the T-top itself might keep things quieter, but that it's not structurally substantial enough (or properly designed) to actually overcome chassis flex... ?