My "New to me" 4cyl Jeep has 100k miles on it right now. I know that with the 4.0L's 100k is just getting started but what about the 2.5Ls? Have you guys seen many people get past the 200-250k mark with a 2.5L? When do they typically die off? What are some common problems with them? And lastly, is it a good idea to use Synthetic oil in this engine or should I stick with the dinosaur variety? 4 quarts with the filter right? Thanks guys!