That's a pity noone saved it. Actually, that was part of the "first generation" of GT2 explorers, based on actual psx and not on emulators, who shared its results on html pages on the 1st generation of the web, and kept in touch with a dozen of "Friend sites" link rather than on forums. They had discovered pretty much everything, I saved what I managed on an .xls file (if you want it I'll give you, but I presume you already know everything it contains, for example the complete track list with their addresses to put into the code, somewhere there was that data and I copied, but I think that's one of the few things that are on the net, yet) but there are lot of things I forgot to save. A guy from 2000s had a wonderful site with detailed info about all the cars with their addresses, engine codes, even tyres and some modifications ones, even each rim with the code to put it on cars eg BMW which can't.
Another site had a translator for codes of each version of the game. One I remember had also a downloadable tutorial about how to modify the 3d models in the game (not only, for example, the Lancer spoiler, the whole polygons on the cars, even if in a rough way)... they knew EVERYTHING and now we are like resurrecting from the middle ages of GT2 esoterism.
Really, there was a lot of interest in these things and I could see most of the sites yet alive (I was 14, 15 and they were already old ones). I don't remember which ones are still accessible, but if you're interested pm me, I'll give you the "ancient" information I have: they're not mine and even if who made them has probably forgotten of their exhistence, is probably wrong to post them publicly without crediting.
The Gt2 tool came also from a site which, if I remember well, provided another good tool too, "Gt2edit.exe" which permitted to manage the garage file directly from the memory card files (for NTSC 1.0). If you find that site it's likely that even the GT2.VOL extractor is there. I would post some pictures of the files in it but they're from the last "format c:" of my pc so they're not there. I used the tool to convert GT2 cars (only models) for "racer", an open-source simulator, not that it was too easy, as texture files were something like 512x512 pictures with every single detail of the car like in a small room thrown in in order to save space, and also, being Gt2 models quite obsolete for year 2006-2007 I gave up and tried - with little success - to make my own.
Good luck if you're going to continue the search!