[Babu]

But when you add on the performance package to the C6 the price goes up to $51k.

Articles I have read say Corvette still claims 0-60 of 4.2 seconds and top speed of 186 mph for the standard Corvette C6 engine.

The Z51 Performance package of which you speak includes a stiffer suspension, beefier brakes and higher gear ratios.

[SVTCobra03]

I can usually beat a C6 from a 40mph roll to 120mph, but after that they just have too much top end for me.