hummmm good question! are you sure it's not?
both cars stock have W rated tires (168mph max), I don't think GM would allow the car to go faster than the tire is rated.
I'm sure the CTS-V could exceed 168 and we know the XLR would if not governored.
Harry...what tires are on your XLR???
...and the CTS-V you drove here, did it top out at 168-169MPH??
Hi 1 XLR,
yes I´ve had the CTS V this fast.
But don`t forget one thing, almost any showing on the speedo is about 5 - 10 % faster than actually going. I drove an A8 and 745 and both are limited at 155 mph or 250 kph but the speedo goes up to 264/267 kph.
I think with my XLR the 289 kph will be about 270 real (168 mph)
I`ve also had the STS N* up to 269 kph.
I have the same tires on my XLR as you do, it`s the 235/50ZR18 97 W and they are allowed here up to 270 kph.
I just wonder why the US models stops exactly at 155, with the speedo-error this would be about 146-148 mph.