sky RL or GXP will have same performance which was the OPs question. Either car can get an E47 (half E85 and half gas) tune from Trifecta and have over 300 to the rear wheels and easily run over stock C5/6 corvettes. I have that tune and have raced a C6 auto tuned with exhaust and ran over him from any speed. The backbone, probeam and LV front would help handling but not straightline speed much if any.
Personally I do not like the corvette stigma........
09 G8GT, Stryker, sport/prem
08 GXP, Mean, Auto
03 Excursion Limited, V10, 2WD and 37s
94 Bronco XLT, 5.8L, very rusty and 35s
07 GXP, Mean, manual-RIP 1Apr13 @14K miles