[keith86a]

GT3:RS is built on widebody shell (same as AWD 911's) which is 44mm wider across the rear axel. It also has a longer wheelbase for improved stability, as well as a split-rear suspension wishbones, stiffer springs, etc. In addition, aerodynamics are also improved, they modified front spoiler and added a massive carbon wing for improved downforce. I'm not sure on how much more downforce the RS has, but its reported to be much more stable at high speeds. Tires are the same, but you can probably fit even wider tires on RS since its a widebody...

P.S. There are also rumors that RS actually dynos 10-15whp higher than regular GT3....