The main focus of these Mkiii's is the aero dynamics. I personally have been to 141, I am not bragging because again that is not to fast when you talk about high speed. I did test the steering at that speed and the car didn't lift and changed lanes swiftly. if you are someone that likes 150+ I would advise you get a wing and maybe even front canards for your front bumper. The car is quite heavy, but a nice gust of wind under that car can call for disaster.
Another important thing is also keeping your engine at a good operating condition. Those HIGH RPMS are not good on stock internals and I have heard of a few people hurting their engines. So the right oil and parts are also crucial.