Thanks Eli,
Yeah from what I've seen GTAV looks to be just an expansion on their current technology, which is pretty common and follows the trend of GTA3 with vice and San andreas. Usually there are a few minor improvements here and there.
Infact you will find files from GTA3 in the GTA4 archives, even lots of files that aren't even used. One that was left in, but looked like it was modified for testing with GTAIV was the Carmods.dat file which had all the universal car mod parts that was used in GTA:SA. Im suspecting that they had bigger plans for GTAIV but decided to release what they had and wait for GTAIV for extra features.
As far as damage system goes, its much more advanced than the previous GTA's which used to swap pannels out with a damaged one when a collision too place. In GTAIV, the speed, angle and location all factor into collisions so they are somewhat dynamic. Some vehicles are more rigid, and some are crumple like tinfoil. The setup is quite advanced and requires a lot of work to get right. Most GTAIV car mods cut corners and dont have things like, dirt, breakable lights, working indicators etc. I think it makes a big differnce in terms of getting it to blend with the game instead of standing out from all other cars.
Ive experimented with increasing damage multipliers, and its pretty halarious when you turn it right up. If you hit a curb half you car would cave in and the front wheel gets jammed somewhere in the engine bay.
Anyway, can't wait for GTAV for PC, who knows when they will release that. Once they've made their money from console sales they tend to release it around a year later.
I have the C210s rival, the Toyota Mark II '78 in the works too