The V6 has a longer service life of 300k miles. I think with all of them I'd be looking at where the mileage would be ending up when I was done with the car. If you plan to put 50k miles on it while you own it, cap the miles at around 150k for what you buy. 163k might be fine if the car has been maintained well and has mostly highway miles.
Average mileage for normal driving on an '08 model should be right around 120k miles figuring an average of 15k miles per year.