Not sure if its just a coincidence but when I try to search for IS 250 start up rattle, pretty much all the search results talk about mk2 IS 250 which it was quite common for mk2.
So since the same 4GR engine was also used in the next gen mk3 model, is the problem still there? or did Lexus/Toyota fix it at some point?
My last Lexus, 2007 IS 250 had that startup rattle and it was very annoying, every time I was wondering if it was gonna rattle this time or not.