Thanks for replying!
My knowledge could be limited but as I know the TVD's the only LSD in the world that uses electronic motors to gain outside wheel speed by 4-5%. I don't know how exactly it works so I assume it could be twitchy or "artificial" like you mentioned while the motors kick in. According to some press (Autocar, Top Gear mag.. etc.), RC F could be tricky to drift. Since all the press cars came with TVD, I wonder it's the reason to blame...
I want to skip TVD because it only comes with an expensive optional package in my country. But what really worries me is the Torsen if it's not enough to make the car oversteer so Lexus brings up the TVD to aid.