October 2006 I joined "GM The Drive" in Las Vegas and selected a Corvette C6 (6.0 V8, 400 hp) and a Hummer H2 SUT (6.0 V8, 325 hp). The C6 seemed to be "slightly" quicker

And regarding the fastest speed I drove, my current Cadillac CTS achives 238 km/h (148 mph) on the German Autobahn until the speed governor comes.