The Ferrari 512TR and the beta version "White Charisma" from Tokyo Xtreme Racer 2.
The "White Charisma" we know today was a rival who drove a white FD3S.
However, recent data mining of TXR2 demos by the TXR community suggests that he was a rival driving a Type-512 (Ferrari 512TR), which was cut content. And, as his nickname suggests, his 512TR is white.
Needless to say, this is a reference to the white Testarossa driven by Ishida in Wangan Midnight, and along with Unknown (Devil Z) and ZERO (Blackbird), suggests that they were homages to key characters that appeared in the early story of Wangan Midnight.
Of course, this choice carried significant risk, and one can certainly understand why they chose not to take it. It's Ferarri.
Infringing on their licensing, which is among the most strict in the world regarding brand image, is risky, and for titles that require legitimate licenses, such as TXR3 and TXR25, the costs required for their licensing agreements are something a small company like Genki could never afford.
In other words, if they had probably made White Charisma's car a 512TR, he would likely have disappeared from the series for many years, just like Zero. From a long-term perspective, the choice they actually made was far more correct.
But even so, I would have liked to see an iconic boss based on Devil Z, Blackbird, and Ishida.