Yes, I feel my IS faster and smoother as well after the break-in period. According to the Lexus IS manual, the break-in period is 1000 miles or 1600 Km but I guess it also depends on the mix of traffic you have. For myself, I did go to highway for a few times which I couldn't avoid and so I don't think my car actually passes the break-in period though there is already 1900Km on it.
I am getting to like the ECT button.
I am getting to like the ECT button.
