im about to fork over a huge amount to get the JDM front end...but as i was reading what it comes with:

Comes with hood, bumper, front lip, head lights with stock bulbs (and balasts if HID), fenders, core support, and side markers.

What do they mean by core support? Is this sufficient enough for a full conversion...I thought you needed a bumper support, radiator support, and bumper reinforcement....? Is that what they mean by core support?

 

I believe they're referring to the radiator core support which is needed for the front end conversion. You can use the whole of the JDM radiator core support, but if your existing USDM core support is ok, then you can just use the "T" section of the JDM one. If you do a search, there have been several threads including one where a member here just used the "T" section of the JDM core support to do his front end conversion. Otherwise, you're going to have to remove the USDM one and weld the JDM one on.