Yes, I did saw that problem. Its nothing really serious though, just kinda weird when doing some moves and stuff :P
Also yes, the Z-buffer can be a bitch sometimes, but I only found depth problems on this game and SW Trilogy. So I think its ok for now.
Now, I was wandering, its me or Daytona 2 its more stressing for the emulator than for example, Sega Rally 2? Well, its 40-car's at the same time after all so I can understand that. Still its kinda "strange" all these weird stutters you get in the same exact turns in each circuit. For example, in the advanced, I ALWAYS stutter for a sec when Im in the first turn, the strange thing is that the framerate recovers a sec later. I suppose that's because its...loading the next part of the track?
Thanks for your time in developing this, and if you need any help to bugfix something, I'll be glad to. My Phenom II x6 + HD5750 is sometimes useful after all :P