i have a 19 yr old celsior (japanese ls400) my mum has an is 250 and rx330 prior to the is250 was an audi tt which was so dissapointing she went back to lexus (before the tt was one of the first is200's in australia). To expect a car to not have anything to ever go wrong with it is just crazy, and to tell me that for $60000 it should be perfect is insane as well. 60k is no longer a stupidly large amount of money to spend on a car remember that the IS range in ENTRY level.
Sure its frustrating that things go wrong (mums had the key finding issue which lexus replaced the whole computer which controls it), but i work on cars every day and can tell you that from a build perspective lexus is by far superior than either BMW or MB. My car is the first run celsior and it is still going unbelieveably well.
The only issues come from the extensive modifications that i myself have done (over 80k worth more than an is250 is new) but compare it to a 20 yr old Merc or BMW and the Lexus is by far the better car.
So for the people out there who can put up with a few rattles and take it back to the dealer once it is sorted you will have many years of enjoyable motoring because i would put money on it your lexus will be driving long after the beemers and mercs.
theres my little rant but i cant believe a few rattles causes so much grief. try putting 20k of stereo in and see where the rattles come from hehehe