Not sure if this is too late but I just saw on Amazon.com that they have the KA pro 600 series 6 qt. mixer on sale (new) for $330.74 - a $169.25 savings off retail! There is also a $40.00 mail in rebate. A very good deal IMO.
The Empire Red model is actually cheaper at only $319.99. I wonder if those might be older ones with the plastic gearbox, which Kitchenaid claims they will replace by extending the warranty. From the Amazon reviews & comments:
RESPONSE FROM KITCHENAID: Thank you for visiting the KitchenAid
I would like to reassure you that our engineering and product teams
have addressed the gear box issue. In fact, we have already
implemented a change in the manufacturing of the Pro 600 Stand Mixers
to a metal gear box. Although these will be changed out on additional
5 qt bowl-lift models that include all metal gearing, the time line on
that is not known at this time. Although a transparent change, this
will insure the long-term durability we expect.
I would like to emphasize to you that should you purchase a Stand
Mixer (with all metal gearing) which has not been assembled with the
upgraded metal gear box, and you should have a problem with your mixer
(as a result of the plastic gear box (failure), we will most certainly
extend your warranty to resolve the issue properly and effectively.
If you have additional questions, feel free to reply back to me. Or,
you may contact either our KitchenAid Customer Satisfaction Center at
1-800-541-6390, or you may visit our secure KitchenAid Live Chat.