Yamauchi provided a summary of what's known about GT HD so far, including the split in modes between classic and premium. Just to avoid confusion, we'll repeat the details here. Classic mode is GT4 in high definition and with a few additional visual enhancements. The mode will be playable exclusively through downloadable cars and tracks. Premium mode is a single player preview of Gran Turismo 5, featuring a full-fledged PS3 graphics engine and detailed tracks and car models.