will the 2011 IS 250 LED headlights fit the ISF? thanks

 

The actual headlamps itself will.... Not quite plug and play though. You're going to need a new flasher relay and some work

 

It'll fit, only 2 of the 3 brackets line up. Some modifications to the bottom bracket, instrument cluster, splicing factory/headlight wires, and relays. It's not an easy task. Look up "2012MY led" in the search bar. You'll find a great thread on all of it.