I didn't see a thread about this topic for the X, so I thought I would start and put my thoughts. I don't normally condone this, but I thought this would be good for 'documentation and research' purposes. First, I'm not speed-demon nor do I have a "heavy foot" (that's usually my wife). Although I'm definitely not averse to a quick start off the line every now and then for fun. I usually drive like a grandma. Usually not more than 5 mph over the speed limit. But I was visiting my brother-in-law and we took the X and his BMW M5 out. There just "happen" to be a nice stretch of flat, isolated, and no other traffic at the time. He took off, so I "followed". In a VERY short time I was up to 114 mph. I barely noticed! And I just have a standard X90D with stock wheels/tires. Overall I think the car handled really well. Only at the end of the stretch it curved up and to the left a bit. If I had planned a bit better, I might have handled the car a bit more elegantly. But I noticed at those speeds (and with a slight curve), the tires were a little 'squishy' (inflated to factory recommendations). They were still VERY well planted on the ground with NO squeal or loss of control. Straight-line is no problem, but curves are a little more precarious for a vehicle of this weight at these speeds. If I had the performance rims/tires it would likely have been a little more controlled. But I will probably never go that speed again, so I prefer the more efficiency (and softer ride) of the stock tires. Was I crazy? I don't think so. It was a safe/isolated road with clear conditions. (The Germans do this all the time, right?) Did I get a ticket? Nope, and I don't plan to get a speeding ticket later. (speed limit was 60mph) Was it a good learning experience? Yes. Now I know, and have no reason to go that fast again. I feel it was also good to see what are the limits in a 'safe' area. Take what you will from this. Thoughts? Experiences? Lessons-Learned?