I just talked to another tire guy and he said the stock tires on my Mirage, Dunlop Ensaves, are very soft tires that don't even have a mileage warranty. He also said it's no big deal to mount 175/65s on a 4.5" wide tire even though the preferred range is 5-6". I really have no choice but to try the 175/65s since the only 165/65s tires I can get are expensive and wear out fast. I'm going to put some cheap 45K tires (175/65) from Walmart for $45 and see how they work first. My next option would be to get slightly wider rims with the 175/65s.
For the record my local Mitsubishi dealer has been completely worthless on this topic. They don't even know what brand of tires they have for the Mirage.