Sorry I was gone for a while there, I got infected and had to reformat and whatnot.

It's the only *.DAT file in the installation, unfortunately. If it's of any help at all, I'll give you the main EXE for it. Matter of fact, it's right here.

I was wondering if anyone had found, or would be willing to find, the archive method used in the Sonic & Knuckles Collection. I have uploaded what I believe to be the GRA here.