Luxury cars, like all car rentals, are typically less costly to rent per week or longer rather than per day. It may be important to consider if renting for an extra day to make up a full week may actually be cheaper in the long run.
Be sure to take the time to do the inspection with the renting agent before pulling the car out of the lot. If there are any scratches or dents be sure to record any marks or visible damage on the contract to avoid being charged for any damages when the car is returned.
