A few days ago I found the download for the Dreamcast version of RV's soundtrack on re-volt.io, and just got around to downloading and listening to it today. I realized that the extended versions of the soundtrack are the same ones I listened to as a kid on my PC copy. It wasn't a legitimate retail disc, rather a gold-colored CD-R with the title written in sharpie. That disc is long gone now, and even if I did have it it'd be scratched to hell, but the music got me thinking about some of the other differences in the version I grew up with vs the official retail release. My memory on some of them is fuzzy, but there are some I'm sure about:
*RC San was still called Dynamo San, and used the same box art as shown on the wiki. I don't believe the stats or texture differ in the retail version
*The disc was copy-protected. Dumbass kid me didn't know what images were so I tried to copy the files from the disc to another in Windows Explorer, didn't work
*The track editor was less polished than in the final release. I remember seeing the "jank non-convex nodes" error message as described here
on some of my tracks during the loading screen, though I don't remember if it had any effect on the AI during the race. I don't recall ever seeing an oldshit directory in the game files either.
*The multiplayer battle maps were completely broken. You couldn't actually see the map or any textures (just black nothingness and the HUD, and maybe the car model but I don't remember) and I don't think you could drive around either. I didn't spend much time trying to figure this out back in the day so the exact details elude me.
*Redbook audio was the same as the Dreamcast version, not the retail PC version.
*The game would crash without fail either during or after the credits after completing all races in the Platinum cup, though I don't believe this stopped you from unlocking Humma and Cougar.
*There was a glitch where flipping your car would sometimes teleport you somewhere else on the track, but that might've been in the retail 1.0 release too.
*Probe UFO was not locked away behind the CARNIVAL cheat, and could be unlocked by collecting all Practice stars for the Platinum Cup tracks.
I don't believe there were any sponsored cars included on the disc, but I do remember the Loaded Chique texture being in tc5. All in all it didn't feel like I had a pre-release version at the time, because it was the complete game with the single-player content (mostly) intact and no implication of the game being unfinished.
Does all this describe a version of the game anyone's familiar with? I wish I could procure the disc to try it out again after all these years, but this is the best I can do. Maybe I'm making a big deal out of nothing