thats about standard for a Lexus my friend, its doesnt get much cheaper if you dont go to the dealer, maybe by 20-30 bucks if you use a full synthetic
---------- Post added July-9th-2011 at 09:15 AM ----------
has there been a change in the tone of the exhaust? if not then it prolly came loose, there are rubber hangers that allow the exhaust to flex and move, if one of them broke or became loose, than it could be hitting the floor boards.
on top of that there are heat shields on certain spots on the exhaust to protect the floorboards from the heat. the welds could have broke off the heat shield and thats causing a rattle also. Not a big deal just have someone look at it when you can