I've never seen a big and small size, but I've owned 4 so far(I've only used a Supra MK III), but 2 of the DSMs were 16 row and 2 were 14 row. They were both the same Hi/Wi/Depth. I've seen a small NPR that looks very similar. The 14 row appears, and is reported by others, to have larger tubes and higher flowing. It comes from the later model Dodge and Mit Conquests.
I sold off all my Z mod stuff and found that I haven't cured the Zbug. I just got a 71 and then found a good 82 zxt + diesel engine for a possible swap. If I can find another 14 row, I thought I'd give it a try. I've seen lots of negs on the restrictive inlets, but not specifically the core. Doug(opie).