Uneven rear wear can be caused by a number of things. I was going to ask if the car had the sports package (with the vlsd). Looks like you answered that in the post above. I'm not sure why the wear is uneven. It would help to know the type of uneven wear. For example, is the inside more worn than outside. Could also be the road crown, but I would think this would be noticeable on the front tires too. And yes, rwd vehicles will wear the rears faster. Just how much more are the rears worn than the fronts? Maybe those 7K miles were harsh/abusive miles...
Agreed, an annual oil change at the least. But then again, you don't really know if it was done or not. How's the color of the oil? Light honey, or dark honey, or black? To the day, it's been exactly 6 months since my last oil change. 3200 miles later, the oil is a dark honey color - not very dark, but more darker than lighter. I'll do an oil change after my road trip (1K miles).
City mileage on these cars is bad. I think I can squeeze out 14-17 mpg by granny shifting and being in 5th gear by 35-40 mph. If mpg is a top concern, you're looking at the wrong car
. There is a price to pay for all that power.