• Download 3DS MaxPax Scene (requires 3DS Max 7 & Brazil)
• Extract self-extracting archive to your 3DS install dir (C:\3dsmax7 for example)
• Read [3DSMAX]\scenes\[game]\DS-AUTOS_[GAME]_MAXPAX-[CAR].NFO for more info
• Load [3DSMAX]\scenes\[game]\[CAR]_b.max
• Apply skin
• Render
• Go and make some coffee =)

The RB4 and LX6 scenes are slightly different to the above process and also require 3DS version 8. Please read the relative NFO for more information.