Εδώ θα βρεις τα πάντα για ελάφρωμα στο Ε46 https://forum.e46fanatics.com/showthread.php?t=460350
Για το καπό γράφει αυτό
8. Front Hood (50lbs) - Replacing the Front Hood with a lightweight fiberglass or carbon fiber hood is a great way to remove some weight around the front end of the car. Total weight reduction will be close to 50lbs or greater depending on the aftermarket hood you choose.. If you dont intend on replacing the entire fron hood you could also remove the sound dampener on the inside of the hood. This should help in cooling your engine a little.