For any addition in the machinery of the car, we would suggest you walk into the nearest service centres. You can click on the following link to see the details of the nearest service centres and selecting your city accordingly
For that, we'd suggest you please visit the nearest authorized service center of Mercedes-Benz as they would be able to assist you. Follow the link and select your desired city for service centre. Moreover, you may visit the official website of Brabus.
Yes, Mercedes Benz G-Class is Powerful, its high ground clearance, suspenssions and different differential modes give it extreme off-roading capabilities and it is luxurious too. Do take a test drive in order to get better clarity. Check out authorised dealership details.