Okay, 1st I'm new here so don't tear me a new asshole =)

I'm swapping an ITR motor into my 88 crx and I just wanna know something. I found a front clip of a USDM ITR for $4000 canadian. But i really want a JDM ITR but unfortunately....just for the engine/tranny, that would run me about $5500.

My question is, how much extra money would it cost me to make my USDM ITR as fast as the JDM ITR? Or even faster? Would the JDM version have more potential than the USDM one in the long run?