What I meant was that you would have had to buy the car new with the sport package that comes with 20's standard. If you didn't get the sport package, your car is electronically limited at a lower speed of 130 mph. If you did opt for the sport package, then you should be able to hit 150. That is how it is in the U.S. anyway.

If you are running winter tires, you may want to be careful testing max speed. I am not sure what the speed rating is for the particular tire you are running on the 18's.