[matt1122]

Our bodies don't actually feel acceleration as much as we feel jerk or surge, which is a change in the rate of acceleration. I believe the T6 engine has a smoother power band (and the Polestar Performance upgrade makes it even smoother), so you won't feel as much jerk with the T6 as you would with the T5, at least at low speeds. This may actually make the T5 more fun to drive around town - unless you're trying to outgun someone alongside you, in which case it may make it more disappointing. On the highway, you may be able to feel the difference between the T5 and the T6, but the T5 is very capable even there.

Having FWD does mean that you will have to fight off some torque steer. It also means more under-steer. This is a significant change in driving dynamics, and if you enjoy the "OH MY GOD, IT IS TRYING TO RIP THE WHEEL OUT OF MY HANDS" feeling of a FWD car, you may miss that with AWD. =) As DWBF1 pointed out, having the dynamic suspension in T6 and the touring suspension in the T5 would further affect the way the car felt, but the dynamic suspension is actually quite stiffer and will make the car handle far better. While it may be a little rougher over bumps, this means high-speed maneuvers on the highway could be a bit safer and easier to handle.

As far as steering goes, and as someone else already mentioned, the T6 has driver-adjustable speed-sensitive steering.

As far as the R-Design goes, it is a T6 AWD with the Polestar Performance Package (+25HP), an even stiffer suspension, a special styling kit, different rims, and the premium package. Certain options are not available with the R-Design: the T5/T6's Sport Appearance Kit and the 4C Suspension. You also are restricted in your color choices if you go with the R-Design, though Passion Red is available on the R-Design but not the T5 or T6.