The term client is used very frequently in conservative US East Coast businesses as well. It isn't incorrect to use it, they are synonymous. In fact, use of the word client lends some professionalism to the business-customer relationship. There are many terms they could have chosen ("user" "buyer" "customer" "client") and I for one think that client is better than others for this particular context ("high end stereo company that deals with the customers on a one-to-one basis with a great deal of professionalism and attention to detail"). The connotation for customer is similar, but then in the world of business, customers get screwed from time to time. Clients are held much closer to the core of a business than that.

That's my psychoword analysis!

Calvin