Hi, thanks for the information. It's interesting to know that the Japanese call the Lexus (they use brandname Toyota and not Lexus in Japan) garage car. Actually, mine is a Toyota Windom (called Lexus ES300 outside of Japan).
I'm not sure whether my car has side impact beam (how to check?). As for the headlight flash or horn sound at high speed, I've not see this on my car. The highest speed I drove my car was only 75mph, due to road speed limits and road conditions in HK. So, not sure if my car has the same problem.