VDIM is an enhanced version of VSC, or if you look at it another way VSC is a component of VDIM. VSC system works like "Oh no, this driver is losing control, let me adjust stuff now and save the day". It is the life jacket thrown to you after you fall off the boat. VDIM works like "Hmmm, getting close to limits of handling, let me make some fine adjustments now to avoid getting close to losing control. It is the higher railing that prevents you from falling off the boat in the first place. I believe the reason VDIM is on the hybrids and not on the regular models is the use of electric power steering.

Here is an interesting Lexus link I found with a short explanation of how this and some other technologies work http://www.lexus-europe.com/technolo....asp?model=All