From this thread:
http://www.lexusownersclub.co.uk/forum/ind...c=50185&hl=QUOTE (Monster-Mat @ May 4 2008, 09:29 AM)

yup just trim the lower inner wing mounting, may need to take a little of the metal that runs under the light aswell
QUOTE (sorted vti @ May 7 2008, 10:45 AM)

right.
just to clear the matter up about is300 headlights on an is200. they do fit but you have to cut the inner wing out. just the piece of metal that the 2 mounting points for the 200 lights bolt onto.
im not sure about standard is300 lights tho as these are aftermarket that i have fitted.
the problem i have now with the aftermarket lights is that i now dont have a main beam due to them being hid. and my original lights arent and i dont have the ballasts to run them. i need to buy an hid kit to fit into the projectors.
There you go, it was Sorted Vti whose fitted them.
You need to trim the wing.
but the way you are saying it ( trim the wing ) sounds like you are on about the bit you can see,