There's really no such thing as "best" for a car. It's going to be a compromise, based on your budget, your goals, and what's currently available.
We really need more information. Like starting with what year MX6 and what engine & transmission? And like Mal said, there is no universal 'best' here. At most, there may be some wheel and tire combinations that are among the best for him, but we have no idea what that might be (never mind who might carry such a package).