There are numerous dealers who do a big mail order business because they discount - places like Gunn Acura, A&H Motorsport, Hoehn Acura, etc. They should all be listed in the Company Directory of the FAQ.
Or, you can get friendly with the folks in the parts department of your local dealer. If you give them your business you may find that they're willing to match the mail order prices (typically 20-25 percent off list).