Well, spotted! I must admit I hadn't even looked at the footage that closely myself to notice that. I've never played SPDX in multiplayer, is there no option to turn the handicap off when you're initially selecting your cars and which courses you're going to race on? I know it was just like a simple on/off setting for PC LANS and Xbox System Link in C2C and also when playing online in Outrun Online Arcade on the PS3. I think the 'player only' bit just means you can disable the multiplayer for your game, if you didn't want someone else joining in. Edit: Actually, that doesn't make any sense as there already is the different single player only code.
Y'know, I've no idea if the Beta Chihiro version of Outrun 2 even supports multiplayer or If it does, if a link-up option is something the Xemu or CXBXR developers are even looking into.
That's interesting about the car stats changing in multiplayer for SPDX. I didn't think there was really a difference between the cars anyway in it, not compared to the OG Outrun 2, where you can really tell the difference in handling between the beginner, intermediate and professional cars.
P.S. Glad you enjoyed the vid!