I need to do two oil changes 1st is a 04 Jeep Grand Cherokee with the 4.7 HO motor 100k miles. The other is a 99 Jeep Grand Cherokee with the standard 4.7 motor 110K. In the past I have been using high mileage motor oils usually Pennzoil or Castrol GTX. These are daily drivers and not high performance vehicles. If you had to choose an oil to use what would it be? Just looking for a good quality motor oil to use in my daily drivers dont have to be high mileage. The manufacture recommends 5w-30 weight. If, someone here has a good reason for me to use the Castrol 0w-30 and spend the extra money by all means let me know. Open to spend the extra money in the 04 for a valid reason but the 99 is not worth it. Thanks for the help.