I am fairly certain that my post said if my goal was to have a track car it would be a GTS. It is irrelevant what NHRA thinks or what safety equipment the GTS has over the RT.
An RT is the quicker viper in every race besides top speed. Its all about the weight, and the GTS has considerably more of it.
You'll notice that not only does the RT have an open roof, but it also has a opening trunk so I doubt that other than crash safety there is a lot of structural strength in the bodies. The GTS does have a top (
http://forums.viperclub.org/general-viper-discussion/629914-double-bubble-visionary-has-passed.html) and a structural surface for the roof and it has a glass hatch instead of full opening trunk. The body has door and rear hatch openings. There is a thread that the RT needs the spare tire for structural integrity, but the spare isn't needed for that in the GTS. I don't understand why you think the GTS is as flexible as the RT? Fiberglass is stronger than steel by weight, therefore it's used in the Viper instead of a steel body.
I did do a search to find the design information that stated that the GTS was stiffer, but couldn't find it this time. I did look through my shop manual and see that the roof structure is a double RTM so you must admit that it has structural integrity and not just a "piece of fiberglas".
I did find this ...
"Viper's steel skeleton is extremely rigid, so the car does not suffer the structural flexing over pavement irregularities that plagues so many convertibles. Still, the huge hood shudders over bumps and the plastic panels behind the cabin squeak. Driving feel is the big difference between the roadster and the GTS coupe. While the roadster has the feel of a kit car, with body panels shaking and quivering over bumps, the coupe is as solid as most production cars. This solid sensation produces more confidence to enjoy the Viper's raw power."
Searching was difficult as there was very little on RT and GTS differences. Most information completely ignored the RT 10. This site also has prices and seems consistent at a couple thousand lower for the R/Ts.
1992-2002 Dodge Viper: Full Review - Consumer Guide Automotive
Ted