Searching revealed 2 slightly different part numbers for both OEM versions of the ITR engine:

NGK-R PFR7G-11 for the JDM B18C-R
and
NGK PFR6G-11 for the USDM version.

Why the difference, compression?? Will it matter any if I use the OEM USDM plugs in aJDM ITR motor??

 

JDM = higher compression and higher combustion chamber temps. Thus the colder plug (7). A PFR6G-11 will be o.k., but you can pick up the PFR7G-11's at your local Acura dealer if you like. It's an optional plug for the 92-95 Legends. Or you can find them at a few places online:
http://clubplug.net/retail_laser_ngk.html
For one.

 

The only difference between those two I think would be the heat range. The numbers 6 and 7 represent the heat range for these NGK spark plugs.

If it helps, I've used the PFR6G-11 in a JDM ITR enging without any issues.

 

Thanks guys

 

If you want the iridium alternative, the ifr7g-11 found in rsx-s is good too