NFSC Unlimiter is a script mod which fixes some issues and makes some improvements for added cars.
Need for Speed: Carbon 
This script adds more customization options for your car, including: - Neons - Front & Rear decals - Tires - Brakes & calipers
You might've noticed that Carbon feels "slow-paced" compared to Most Wanted, this mod aims to fix that and more!
NEED FOR SPEED UNDERGROUND WIDESCREEN FIX Version 1.4 and a No-CD patch is recommended before installing.
+ Lap, Pursuit Time (for Pursuit Tag) and Opponent Controllers > You can have from 0 (which makes the race unlimited) to 127 (Really long races) laps/minutes. > You can have from 0 (forever alone) to 29* (the biggest race wars) opponents.
Road Textures Track Barriers by MΛHΛ Night Sky Some particles effects