I don't know if you can disassemble the thing and put it backwards for different ramp rates. They're both "2 ways" or both "1.5 ways" because well, 2 ways and 1.5 ways are the same 'thing'
I do not know for sure, but I believe the 38420-RSS15-B5 is the 1 way, and 38420-RSS20-B5 is the two way.
In other words, I predict Nissan considers this:
to be a 1.5 way.
No idea what actually happens when it arrives/you disassemble it. It would be an excellent question to ask Nismo directly! I somehow doubt you will get an answer though, I feel you would be the first person to document what you encounter when you open the box and the internet would be grateful.
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