VIP garage needs qualified engineers and technicians, preferably off from the Benz and Beamer assembly lines and body shops, with tools and licenced diagnostic scanners and softwares, kindly rephrase your requirements also write to the car manufacturers to enroll your business for the technical support trainings so that your crew remain up to date with the technology they will work uopn. An accreditation with ISO for processes and Automotive regulatory authority will be an added value.
Any thing less will be a road side shack with mistri and choota setup.