I've been busy answering e-mail, just finally making it to the forums...
The best bet would be to stick with the 275/40R17's all around for a couple of reasons. You can rotate to add to the life of the tires and a 9 inch wheel is maxed out with a 275/40.
Thx for the response, unfortunately i've already ordered the 285's for the rear, hopefully i won't have any clearance issues considering my car has been lowered 1.25 all the way around.