Okay, as I understand it, the early JDM B20s and USDM B20b's have the TALL IM with the port runners as long as my leg. And the later JDM and USDM B20z's have the shorter IMs. (Please correct me if I'm misinformed...)

Has anyone ever done a back to back dyno comparison of these two manifolds to see what the performance difference is? If so, please share your your wisdom and experience with us, here.

For everyone reaching for the keyboard to tell me they both suck or that the tall one won't fit under the hood, save the effort. I'm looking at a rule book that does not allow the use of aftermarket manifolds, and I'd happily cut a hole in the hood for a performance advantage. Plus, I've got one of each sitting in the garage. Just curious about how different the torque curves and top-end graphs might be.

 

No help?