Fastrack question

In what Fastrack were the 97-98 base models and Type SH separated and the base model given a lower minimum weight of 2825#? The first I saw anything about it was in the 2005 GCR that I just downloaded.
The only performance difference between the two models is the ATTS which is a computer controlled differential. Since differentials are open in IT anyway I can't see why the two models should be separated. What makes this even harder to swallow is that in my Type SH model I took out the ATTS system/transmission and replaced it with a base model transmission. Since the two models are now separated my car is illegal unless I put back on the old ATTS system/transmission. I had too many problems with that old setup so I can’t see going back to it.