I think you got it covered SRT SIX.
Faridk89,
Thinking that the Limited was more agile probably comes from three points.
1. Less power... the more power you have the more you tend to use/abuse it and the car will enter turns much faster and you will be more aggressive exiting the turns too.
2. The Limited has softer suspension which can give the illusion of being more agile as the vehicle's tires respond more quickly than the bulk of the vehicle weight.
3. The SRT6 weighs a bit more. It's like having another 200 pounds of sandbags on your hood near the windshield.
HDDP and I can both attest to the fact that the SRT6 is just as agile or more so as the Limited or Base models.