Sorry I couldn't find this answer throughout club Lexus but i am sure many people know the answer. Does the 2nd gen rear diffusor fit the 3rd gen IS? Got someone that has a carbon fiber rear diffusor local to me and was wondering. Sorry for the noob question lol.

 

No it will not fit.

 

2nd no it will not fit from me.
bumper is a totally different design.

there are plenty of 3IS specific diffusers to choose from though so its not like your choices are limited.