I'm always leery of assuming a setup like that has been assembled based on critical listening by the wealthy and famous owner. There are a few potential pitfalls. The biggest is the "freebie" factor. If Stone did try to get companies to give him equipment for free, then the system has less to do with what he found to sound the best and more with what company thought they could write off a set of speakers as an advertising expense. Second is the potential for the custom installer to limit the options. If a wealthy person walks in to a custom installer's shop and says "set me up with a great system," that installer is going to start pulling from the lines he reps. That will greatly restrict the number of brands being considered for inclusion. Third is personal taste. Does what sounds good to Oliver Stone sound good to me? There is a personal taste factor, especially with speakers, that can't be overlooked.

All that being said, this approach can work out - after all, whoever was doing the install for Stone wouldn't put bad speakers in there.