ML63 AMG

Lightweight crank pulleys always work, they have been proven for decades, but most of the gains come from 1500-5000rpm. They don't make a huge difference in peak HP close to redline just bc the motor is already spinning so fast (unless they are under driven which the AMS one was not for reliability reasons).

It's a great mod for the price and it helps fuel efficiency too. If you want more torque and acceleration (especially in 1st-3rd gears) it's a great mod... Won't do much in 5th gear bc the inertia at those speeds is already so high that it's not very beneficial.